The Relationship between Green Country Image, Green Trust, and Purchase Intention of Korean Products: Focusing on Vietnamese Gen Z Consumers

: This study aims to extend the stream of country image research through an empirical test primarily focusing on the relationship between the green country image of Korea, as well as the green trust and purchase intention of Korean products considering Vietnamese Generation Z (hereafter Gen Z) consumers. Data were collected in November 2019 through an online survey, and 440 data samples were identiﬁed and used for conducting the data analysis. The sample was divided into Vietnamese consumers residing in Korea and Vietnam. Firstly, an examination of the variance revealed that Vietnamese Gen Z consumers residing in Vietnam (VZV) displayed less positive perceptions of the constructs measured compared to Vietnamese Gen Z consumers residing in Korea (VZK), including cognitive green country image (CGCoI), a ﬀ ective green country image (AGCoI) of Korea, and also green trust (GT) and purchase intention (PI) of Korean products. Second, results from the structural equation model of VZV showed that CGCoI had a signiﬁcant impact on the PI, while AGCoI had a signiﬁcant impact on GT. Conversely, for VZK, it was found that CGCoI had a signiﬁcant impact on PI, and that AGCoI had a signiﬁcant impact on both GT and PI. Thirdly, the results of comparing the path coe ﬃ cient between VZV and VZK showed that the impact of CGCoI and AGCoI on PI were stronger for VZK, whereas the impact of AGCoI on GT was stronger for VZV. Based on these ﬁndings, the study discusses practical and theoretical implications for future green marketing practices in Vietnam.


Introduction
Vietnam has achieved rapid developmental progress since the 1986 Doi Moi reforms. Following this, Vietnam sustained a high economic growth rate that reached lower middle-income status in 2010. Real per-capita gross domestic product (GDP) tripled between 1990 and 2015, peaking at 7.1% in 2018 [1]. In line with the issues of rapid economic growth, Vietnam faces significant environmental challenges as a result of its growth outcomes. Fortunately, the government of Vietnam has shown a strong inclination towards the determination of sustainable growth in line with its rapid economic growth [2]. Meanwhile, bilateral trade between Vietnam and Korea is projected to continue growing, while Vietnam is expected to become Korea's second-largest exporting destination in 2020 thanks to a free trade agreement (FTA) between the two countries, which came into effect in December 2015 [3]. Therefore, it becomes a critical factor and opportunity for Korean and other international marketers to understand the Vietnamese consumer's country image perceptions of Korea, as the volume of Korean consumer goods exported to Vietnam is expected to gradually increase over the coming years. In addition, younger Vietnamese consumers progressively show a greater concern with regard to environmental issues, thus it is crucial for international marketers to understand the relationship between the green country image of Korea and the consumption behaviour of young Vietnamese consumers.
Country-of-origin image (CoI) remains one of the most popular research topics in international marketing with hundreds of studies published since the 1960s [4][5][6]. Many studies found that a favourable CoI is positively related to a consumer's evaluation and consumption behaviour of foreign products [7][8][9][10]. Recent studies related to CoI consider the multi-dimensionality of the construct when operationalizing CoI [11]. Therefore, the current study aims at extending this stream of research. To the author's knowledge, very few studies have focused on the environmental context of CoI, while even fewer studies, or any at all, have considered green country image (GCoI) with regards to the multi-dimensional nature of the construct. Recently, many countries have applied sustainable development goals (SDGs) to their national economic development model [12]. As a result, a positive green country image could be seen as an effective international marketing communication factor for countries implementing such policies [13]. Therefore, the current study focuses on the impacts of the cognitive and affective dimensions of green country image on the purchasing behaviour towards foreign products. Meanwhile, Gen Z has become the most spotlighted consumer group for green marketers. The Gen Z consumers are those individuals who were born in 1995 or later [14,15] and are known to actively adopt green products [16] based on their intrinsic pro-environmental values [17] and also motivate others to adopt sustainable practices [18]. The average age of the population in Vietnam is under 27, and younger Vietnamese consumers are relatively open towards foreign products [19]. Therefore, the findings of this study are expected to provide green marketing implications to multinational firms targeting Vietnamese Gen Z consumers. Additionally, for researchers, this study is expected to shed further light on a critical construct, namely, GCoI in the international marketing arena that many researchers, until now, were not able to fully explore.
This study is structured as follows. Firstly, a proposed model is introduced after a thorough literature review of the research constructs. In the model, GCoI is empirically tested as a multi-dimensional construct, including cognitive and affective dimensions. Subsequently, the study tests the relationships between GCoI, GT, and PI. In addition, the study compares path coefficients among the two Vietnamese Gen Z consumer groups residing in Vietnam and Korea in order to improve the explanatory power of the study model. The last section of the paper specifies the main conclusions, theoretical and practical implications, and the current study's limitations.

Gen Z Consumers in Vietnam
Vietnam has recently become the most attractive market among the list of Southeast Asian countries for Korean companies to invest in [20]. The population of Vietnam reached approximately 97 million in 2018, while 70% of the population is under the age of 35 [21]. In addition to this, political and economic reforms in the country have led to remarkable economic development in Vietnam, improving the quality of life for the population over the past 30 years. However, Vietnam's rapid economic development has resulted in many environmental complications for the country, such as higher levels of carbon dioxide due to greater industrialization, and further natural anomalies such as greater storms and flooding, and rising sea levels attributed to global warming [22]. Therefore, the Vietnamese government and various social organizations are trying to improve social environment consciousness via environmental policies and education. As a result, Vietnamese people are starting to show a greater concern regarding the environment and policies geared towards its sustainability [22,23]. However, despite the enormous potential for green marketing in Vietnam, there have been few studies focused on the pro-environmental consumption behaviour in emerging markets, such as Vietnam, compared to studies focused on Western, or more developed nations [24,25].
Young consumers represent a promising market for green products. Vietnam is one of the youngest countries in the world based on their age structure, and younger generations are generally known to be more attentive to social issues such as green consumption [26][27][28][29][30]. Gen Z is an emerging consumer generation and refers to the generation that was born between the second half of the 1990s and the mid-2000s. The number of people belonging to Gen Z exceeds more than 14 million in Vietnam [31]. Gen Z shows a high interest in social issues such as environmental matters, social responsibility, and gender equality [31].
Several researchers argued that younger adults tend to have higher awareness and concern about environmental issues, and therefore show a more positive attitude towards green products [28][29][30][31]. However, some researchers have found contradictory evidence pointing to the fact that younger consumers do not support environmental regulations and are less attentive to eco-labelling than older consumers [32][33][34][35]. Jain and Kaur attributed the results of their study findings to the financial constraint of younger consumer groups [29]. Contradictory results have also been found in empirical studies on young consumers groups in Vietnam [36]. De Koning et al. argued that young Vietnamese consumers show lower level of purchasing intention for green products, because they lack the opportunity and ability to practice sustainable consumption [22].
Given these inconsistencies of previous studies' results, there is a need for further analysis into the green consumption behaviour of younger Vietnamese consumers. As a final thought on the issue, the income of Gen Z consumers in Vietnam is on the rise, and this younger generation is exerting an ever-greater influence on household consumption. Moreover, younger Vietnamese consumers pay a lot of attention to the world around them and clearly prefer brands that stand for a good cause [31]. Therefore, marketers who wish to engage with this new generation in Vietnam need to explore the implications of using the term "green" [37].

Green Country Image
The impact of country-of-origin (COO) on consumer's perceptions, preferences, and purchasing behaviour is one of the most widely researched topics in the international marketing literature [38][39][40]. A full-scale study of the country image (CoI) began in the marketing field from the early 1960s. Schooler found that each country has its own CoI, and CoI affects consumer preferences, their evaluation, and the purchasing intention of products from a specific country [38]. CoI is defined as a "general perception of products made in a specific country", and CoI is distinguished from the general country image [39,40]. The most popular definition of macro CoI was originally put forward by Martin and Eroglu, who defined it as "the total of all descriptive, inferential, and informational beliefs one has about a particular country" [41]. Verlegh and Steenkamp comprehensively reviewed 41 studies on CoI published in U.S. marketing journals from 1980 to 1996 and found that CoI consisted of cognitive, affective, and normative aspects [9]. CoI serves as a cue to overall product evaluation and quality attributes in cognitive aspects [42], and the affective aspects of CoI provide symbolic and emotional values closely related to status, authenticity, and exoticness [43][44][45]. Further, the normative aspects of CoI refer to consumer's social and personal norms in that purchasing domestic products may be regarded as "a right way of conduct" because it supports the domestic economy [46][47][48][49].
Although a great deal of studies on CoI exist, the green country image (GCoI) is a new construct in the international marketing field. In tourism literature, some researchers presented the green destination image as a new construct that focused on eco-friendly tourists' behaviour [50,51]. In addition, within the marketing literature, the green brand image or green corporate image has also been examined as an important variable to increase the consumer's engagement in a specific brand or company [52][53][54]. However, studies of GCoI on consumption behaviour of foreign products from the international marketing perspective are rarely found. Therefore, this study aims to verify whether GCoI will lead to a positive consumer attitude and behaviour towards foreign products and to fill the gap in the literature. Corrigan demonstrated that Ireland's green image drives Irish export growth [55]. Furthermore, green country image can be divided into cognitive and affective dimensions based on previous studies' arguments that country image is a multidimensional construct [9,[56][57][58][59]. Each dimension is also expected to have a positive impact on a consumer's attitude and consumption behaviour towards foreign products.
Meanwhile, Fishbein and Ajzen's theory of reasoned action (TRA) can be applied to explain the process through which GCoI ultimately leads to purchase behaviour of foreign products [60]. Fishbein and Ajzen argued that the best way to measure an individual's behaviour is to measure the intention to execute an action [60]. In addition, they explained that the intention of performing a specific action could be estimated by the attitude towards a behaviour and the feeling of whether the action was an important issue for the people enacting it [60]. TRA has been used in various studies to date and has also been used in various country image studies because it improves the understanding of consumer attitudes and behaviour through relatively simple measurements [39,61,62]. Therefore, this study assumes that CGCoI and AGCoI of Korea have positive impacts on the purchase intention (PI) of Korean products based on the theoretical and empirical evidence presented above. Thus, the following hypotheses are proposed.
Hypothesis 1 (H1). Cognitive green country image has a positive impact on purchase intention.
Hypothesis 2 (H2). Affective green country image has a positive impact on purchase intention.

Green Trust
Trust is defined as "the belief that counter party's word or promise is reliable, and he/she will fulfil his/her obligations in their exchange relationship" [32]. Schurr and Ozanne found that a low level of trust leads to unfavourable attitudes and poor communication [32]. Trust is also defined as a belief that a party will act in the best interests of the other party, and it is an essential factor in building a better exchange relationship [63,64]. Geyskens et al. defined trust as "the extent to which a firm believes that its exchange partner is honest and/or benevolent" in their meta-analysis of studies on trust [65]. Moorman et al. defined trust as "a willingness to rely on an exchange partner with whom one has confidence" [66], and Morgan and Hunt defined trust as "a confidence in an exchange partner's reliability and integrity" [67]. Doney and Cannon defined trust as "a perception of credibility and benevolence of a target of trust", based on the social psychology literature. In particular, it is notable that Moorman et al. pointed out that trust is a construct containing belief, feeling, or expectation about an exchange partner, which can be judged from the partner's expertise, reliability, and intentions [68]. Ganesan argued that trust consists of credibility and benevolence. Credibility was defined as an expectation of a party's behaviour, and benevolence was defined as a party's intention and motivation [69].
As discussed in previous studies about trust, trust is a construct that has been widely studied in a variety of social science fields [70]. In particular, trust is regarded as an important factor in forming and developing market relations in the marketing field [32,63,[71][72][73]. Numerous studies found that trust can mediate the relationships between buyers and sellers, and lead to greater customer loyalty towards a company [74][75][76]. In other words, numerous empirical studies found that trust is an important variable in building and developing customer relationships [76][77][78]. Flavián et al. and Mukherjee and Nath found a positive relationship between brand image and customer trust [79,80]. Therefore, this study defines trust as "an individual's psychological state that may involve cognitive, affective, and behavioural components" according to the understanding of trust furnished by the previous literature. This study also partially adopts the definition of green trust, from Chen, as: "a willingness to depend on a product, service, or brand based on the belief or expectation resulting from its credibility, benevolence, and ability related to its environmental performance" [52].
Based on previous literature reviews, this study assumes that the more positive the CGCoI and AGCoI are, the higher the GT of foreign products. GT is defined as a belief or expectation resulting from its credibility, benevolence, and ability regarding the pro-environmental performance of foreign products. In addition, Flavián et al. found that trust can diminish the consumer's perceived risk and simultaneously increase the probability of purchase at the moment of a transaction's execution [79]. In other words, they found that trust is positively related to purchase behaviour. Gefen and Straub also found that consumer trust influences purchasing decision [81]. Based on previous literature reviews, this study proposes the following hypotheses, H3 to H5.

Hypothesis 3 (H3).
Cognitive green country image has a positive impact on green trust.

Hypothesis 4 (H4).
Affective green country image has a positive impact on green trust.

Hypothesis 5 (H5).
Green trust has a positive impact on purchase intention.

Data Collection and Sample
The original English survey instruments were translated into Vietnamese based on the back-translation technique [82]. A Korean international marketing professional translated the survey instruments from English to Korean, and then a Vietnamese-Korean bilingual graduate student translated the Korean survey instruments to Vietnamese. Thereafter, another Vietnamese-Korean bilingual graduate student, who was not informed of the first translation, translated the Vietnamese survey instruments to Korean. This process continued until linguistic equivalence between the Korean and Vietnamese versions were ensured. Finally, two other Vietnamese-English bilingual researchers performed the same prior process for ensuring the equivalence of the survey instruments. After cross-checking the translated versions, a two-round pre-test was conducted prior to data collection. For diagnosing and eliminating potential problems relating to instrument clarity and question wording, 30 Vietnamese undergraduates were invited to participate in a two-round pre-test. The final version of the questionnaire was completed based on the feedback received from the pre-tests.
This study simultaneously conducted a survey in two locations, namely Korea and Vietnam. This was done to identify possible distinctions between the two sample groups. This study selected an online survey method to reduce costs and increase efficiency and response rates. An online survey was conducted using Google Forms, which has become a popular survey administration application for collecting questionnaires from various locations. In Korea, the author and several Vietnamese graduate assistants conducted an online survey, and a Vietnamese professional researcher assisted further with the online survey based on the author's directions. The questionnaire was distributed to undergraduate students at D university in Korea and T university in Vietnam. This study adopted online survey, which allowed for the rapid process of surveys for respondents who were geographically diverse [83]. The survey link was promoted to students enrolled in D university at which the author works in Korea, and T university, which is a sister Vietnam university of D university. Through this, the author could be readily informed on the survey's progress through close contact with a faculty member at T university in Vietnam. The survey was conducted in November 2019 and took about two weeks to finish collecting about 250 responses from each country. After data screening, 221 completed questionnaires from Korea, and 219 completed questionnaires from Vietnam were used for the final analysis. The eliminated questionnaires included those in which 50% of the questions were unanswered and missed data for dependent variables such as purchase intention were prevalent [84].
The respondents in this study were Vietnamese university students under 23 years of age who are residing in Vietnam or Korea. The total number of surveys used for analysis was 440, which included 245 females (52%) and 195 males (48%). There were 171 (39%) respondents aged between 18-20 years and 229 respondents (61%) aged between 21-23 years.

Study Model
The study develops a conceptual study framework that reflects the impacts of CGCoI and AGCoI on GT and PI based on the literature review (see Figure 1). Both CGCoI and AGCoI of Korea are expected to affect consumption behaviour and, more specifically, GT and PI of Korean products for Vietnamese Gen Z consumers. In addition, this study aspired to identify which distinctions exist between Vietnamese Gen Z consumers residing in Vietnam (VZV) and Vietnamese Gen Z consumer residing in Korea (VZK) in the structural model. The study model is presented as shown in Figure 1.

Definitions and Measurements of the Constructs
This study established four constructs-CGCoI, AGCoI, GT, and PI-and developed operational definitions and measurements of these constructs based on previous studies on country image, trust, and purchase intention. The operational definition and measurement instruments for constructs are as follows: First, CGCoI was conceptualized as "a set of consumer's cognitive perceptions linked to environmental commitment and the current status of a country". The measurement of CGCoI included three items: (1) Korea has a good reputation in environmental matters, (2) Korea has high environmental protection standards, and (3) Korea has highly advanced environment protection systems [41]. Second, AGCoI is measured using items adapted from Crites et al. [84]. AGCoI was conceptualized as "a set of consumer's emotional perceptions linked to the environmental status of a country". Out of the original 12 pairs of affective measurements in Crites et al., three items were chosen as AGCoI measurement items in accordance with the content and construct validity test [85,86]. Three semantic pairs for affective measures included good/bad, happy/annoyed, and positive/negative. The measurement instrument was composed of three reversed items: (1) When I think of the environment in Korea, I feel bad. (2) When I think of the environment in Korea, I feel annoyed. (3) When I think of the environment in Korea, I feel negative. Third, this study defined green trust as "a willingness to depend on a product from a country based on the belief or expectation resulting from its credibility, benevolence, and ability about its environmental performance" [51]. The measurement of green trust includes four items: (1) You feel that Korean products are environmentally reliable. (2) You feel that the environmental performance of Korean companies is generally dependable. (3) Korean companies' environmental concern meets your expectations. (4) Korean products keep promises and commitments for environmental protection. Fourth, the purchase intention toward Korean products was conceptualized as "an intention to purchase Korean products voluntarily and actively". The measurement of PI includes four reversed items: (1) I would never buy products made in Korea.
(2) When buying products, I will not buy Korean made products.
(3) I do not like the idea of owning products made in Korea. (4) Whenever possible, I will avoid buying products made in Korea [87]. All questions were measured using a seven-point Likert scale (1: strongly disagree; 7: strongly agree).

Data Analysis Methodology
The data analysis methods used in this study were as follows. First, frequency analysis was conducted to investigate the demographic characteristics of respondents. Second, multivariate analysis was conducted to examine differences of the constructs between VZV and VZK. Third, correlation analysis was conducted to examine the correlations among variables. Fourth, the feasibility and reliability tests on instruments of each variable were conducted to verify the predictability and accuracy of variables. Fifth, structural equation modelling (SEM) analysis was conducted to verify the study model and obtained the empirical results in order to test hypotheses using AMOS 22.0 [88]. Lastly, to examine differences of path coefficients between VZV and VZK,

Definitions and Measurements of the Constructs
This study established four constructs-CGCoI, AGCoI, GT, and PI-and developed operational definitions and measurements of these constructs based on previous studies on country image, trust, and purchase intention. The operational definition and measurement instruments for constructs are as follows: First, CGCoI was conceptualized as "a set of consumer's cognitive perceptions linked to environmental commitment and the current status of a country". The measurement of CGCoI included three items: (1) Korea has a good reputation in environmental matters, (2) Korea has high environmental protection standards, and (3) Korea has highly advanced environment protection systems [41]. Second, AGCoI is measured using items adapted from Crites et al. [84]. AGCoI was conceptualized as "a set of consumer's emotional perceptions linked to the environmental status of a country". Out of the original 12 pairs of affective measurements in Crites et al., three items were chosen as AGCoI measurement items in accordance with the content and construct validity test [85,86]. Three semantic pairs for affective measures included good/bad, happy/annoyed, and positive/negative. The measurement instrument was composed of three reversed items: (1) When I think of the environment in Korea, I feel bad. (2) When I think of the environment in Korea, I feel annoyed.
(3) When I think of the environment in Korea, I feel negative. Third, this study defined green trust as "a willingness to depend on a product from a country based on the belief or expectation resulting from its credibility, benevolence, and ability about its environmental performance" [51]. The measurement of green trust includes four items: (1) You feel that Korean products are environmentally reliable. (2) You feel that the environmental performance of Korean companies is generally dependable. (3) Korean companies' environmental concern meets your expectations. (4) Korean products keep promises and commitments for environmental protection. Fourth, the purchase intention toward Korean products was conceptualized as "an intention to purchase Korean products voluntarily and actively". The measurement of PI includes four reversed items: (1) I would never buy products made in Korea.
(2) When buying products, I will not buy Korean made products. (3) I do not like the idea of owning products made in Korea. (4) Whenever possible, I will avoid buying products made in Korea [87]. All questions were measured using a seven-point Likert scale (1: strongly disagree; 7: strongly agree).

Data Analysis Methodology
The data analysis methods used in this study were as follows. First, frequency analysis was conducted to investigate the demographic characteristics of respondents. Second, multivariate analysis was conducted to examine differences of the constructs between VZV and VZK. Third, correlation analysis was conducted to examine the correlations among variables. Fourth, the feasibility and reliability tests on instruments of each variable were conducted to verify the predictability and accuracy of variables. Fifth, structural equation modelling (SEM) analysis was conducted to verify the study model and obtained the empirical results in order to test hypotheses using AMOS 22.0 [88]. Lastly, to examine differences of path coefficients between VZV and VZK, configural invariance, metric invariance, and scalar invariance tests were conducted sequentially [89,90].

Validity and Reliability of Measurement Instruments
This study adopts a series of exploratory factor analyses (EFA) approaches using maximum-likelihood estimation and conducting oblique rotation to identify the smallest number of meaningful latent variables or factors, as measurement items of constructs selected from more than one source [91]. The results of the EFAs show that the factorability of the data is statistically significant (p < 0.001), and the Kaiser-Meyer-Olkin (KMO) values predominantly exceeded 0.7 [91,92]. In addition, reliability analysis using Cronbach's alpha was performed to examine the internal consistency reliability of the construct measurements. The results revealed that the Cronbach's alpha coefficients ranged from 0.61 to 0.90. The factor analysis of the four constructs is shown in Table 1. The degree of inter-relation for the measurement items of each construct was measured through convergent validity and was estimated by calculating the average variance extracted (AVE) and composite reliability (CR). A strong interrelation of items was considered based on the reference value (AVE ≥ 0.50 and CR ≥ 0.70). According to the tests of reliability and validity, it seems that adequate reliability and validity exist in this study. This study referred to previous related research to design the questionnaire. Thereafter, two pre-tests were conducted and revision on the original questionnaire was made before the main survey was conducted. Therefore, it is assumed that the measures presented in this study have content validity.

Analysis of Variance (ANOVA) Test
Mean (M) and standard deviation (S.D.) of constructs are shown in Table 2. Mean and S.D. are calculated using constructs identified during the factor analysis. The respondents, on average, demonstrated positive attitudes towards the GCoI of Korea (CGCoI = 5.05, AGCoI = 4.68). For the mean differences between VZV and VZK, the mean of GCoI of VZK (CGCoI = 5.26, AGCoI = 4.82) was higher than that of VZV (CGCoI = 4.84, AGCoI = 4.53). Simultaneously, VZK showed a higher level of GT for Korean products (M = 5.04) than VZV (M = 4.78). Notably, VZV showed relatively lower levels of PI for Korean products (M = 3.45) than VZK. As a result of the F-test of equality of variances, two groups are different in terms of the mean for each construct. This shows that VZK tend to recognize Korea as an environmentally advanced country more than VZV do. However, for VZV, the PI was lower than GCoI and GT. Thus, it can be predicted that there may be factors that hinder the GCoI of Korea and GT of Korean products from being connected to PI in VZV.  Table 3 shows the correlation matrix. The variables are calculated using constructs identified during the factor analysis. This study uses the Pearson correlation coefficient to examine the strength and direction of the linear relationship between constructs. The correlation coefficient ranges in value from 0.06 to 0.55, and some correlations between variables are not significant when comparing the p-values at a significance level of 0.05 (two-tailed). Although some low Pearson correlation coefficients are present among some variables, it does not mean that no relationship exists between the variables. The variables may have a nonlinear relationship. All correlations between constructs were less than 0.6, demonstrating that multicollinearity was not likely to affect the measures [91].

Results of SEM Analysis
In order to verify the current study model and hypotheses, the study used structural equation modelling (SEM) analysis for each of the two consumer groups. In SEM analysis, goodness-of-fit index (GFI) assesses relative extent of variance and covariance together explained by the measurement model, and root-mean-square error of approximation (RMSEA) is used to measure the absolute fitness. In addition, normed fit index (NFI) and adjusted goodness-of-fit index (AGFI) are further employed to assess incremental fit of each measurement model, which indicates the level of model fit in relation to null model. As a result of SEM for VZV, most of the fitness indexes (χ 2 = 166.122 (df = 71), p < 0.001; GFI = 0.907, AGFI = 0.863, NFI = 0.887, RMSEA = 0.078) meet the levels of acceptance of Forza and Filippini (χ 2 /df < 5.0; GFI ≥ 0.80; AGFI ≥ 0.80; NFI ≥ 0.80; RMSEA < 0.08) [93]. The hypotheses test results are shown in Table 4. CGCoI of VZV has a significant positive effect on PI but has no significant direct effect on GT. AGCoI of VZV has a significant positive effect on the GT but has no significant direct effect on PI. In addition, for the VZV sample, GT showed no significant effect on the PI of Korean products. According to the results of the study, CGCoI and AGCoI of VZV showed different influences on GT and PI. The fit of the structural model to VZK is also considered satisfactory (χ 2 = 189.634 (df = 71), p < 0.001, GFI = 0.897, AGFI = 0.847, NFI = 0.857, RMSEA = 0.088). As shown in Table 4, CGCoI and AGCoI of VZK have a statistically significant impact on the PI of Korean products, and AGCoI of VZK has a statistically significant impact on the GT of Korean products. Finally, GT shows no statistically significant impact on the PI of Korean products in the VZK sample.  Based on the results of the path analysis using the SEM, it was found that CGCoI of Korea had a significantly positive effect on the PI of Korean products for both consumer groups. However, AGCoI of VZK increase the overall GT and PI of Korean products, while AGCoI of VZV showed an increased GT of Korean products. Therefore, H1, H2, and H4 are supported for VZK, while H1 and H4 are supported for VZV. Figure 2 summarizes the results of the green country image model for Vietnamese Gen Z consumers and shows the comparison of the differences of path coefficients of CGCoI and AGCoI on GT and PI between VZV and VZK [89,90]. products. Finally, GT shows no statistically significant impact on the PI of Korean products in the VZK sample. Based on the results of the path analysis using the SEM, it was found that CGCoI of Korea had a significantly positive effect on the PI of Korean products for both consumer groups. However, AGCoI of VZK increase the overall GT and PI of Korean products, while AGCoI of VZV showed an increased GT of Korean products. Therefore, H1, H2, and H4 are supported for VZK, while H1 and H4 are supported for VZV.   Figure 2 summarizes the results of the green country image model for Vietnamese Gen Z consumers and shows the comparison of the differences of path coefficients of CGCoI and AGCoI on GT and PI between VZV and VZK [89,90]. To compare the differences of path coefficients across the two Vietnamese consumer groups, an unconstrained model test and measurement weights test were conducted sequentially [68,[71][72][73]. The model fit index is shown in Table 5. For the configural invariance test, configural congruity was To compare the differences of path coefficients across the two Vietnamese consumer groups, an unconstrained model test and measurement weights test were conducted sequentially [68,[71][72][73]. The model fit index is shown in Table 5. For the configural invariance test, configural congruity was confirmed as the goodness-of-fit indices of comparative fit index (CFI), and RMSEA were acceptable. Next, the test for metric invariance examined whether the factor loadings were equivalent across the groups by verifying the χ 2 difference between the unconstrained model and the constrained model using equalization constraints. The metric congruity was confirmed because the χ 2 difference between the two models was not statistically significant, when considering the degrees of freedom.  Table 6 shows the results of comparing the path coefficients between VZV and VZK. Results confirmed differences in the impacts of CGCoI on PI between VZV and VZK as being statistically significant. In addition, the comparison of the impacts of AGCoI on GT between VZV and VZK was statistically significant. Lastly, the differences of GT on PI between VZV and VZK was statistically significant, however, the path coefficient was not statistically significant between GT and PI for both the VZV and VZK samples. Therefore, the comparison of the path coefficient between VZV and VZK should be interpreted based on the relationships between CGCoI and PI and between AGCoI and GT.

Conclusion and Implications
The study findings show that the VZV sample was found to display lower perceptions of CGCoI, AGCoI, GT, and PI when compared to the mean of the VZK sample. Second, from the results of the SEM analysis, CGCoI has a significant impact on the PI of Korean products, and AGCoI has a significant impact on the GT of Korean products for VZV. For VZK, the CGCoI has a significant impact on the PI of Korean products, and the AGCoI has a significant impact on both the GT and the PI of Korean products. Therefore, H1 and H4 are supported for VZV, while H1, H2, and H4 are supported for VZK. Lastly, the path coefficient comparison across VZV and VZK was conducted. The comparison result shows that, for VZK, the impact of CGCoI of Korea on PI of Korean products was stronger than that for VZV, and for VZV, the impact of AGCoI of Korea on GT of Korean products was stronger than that for VZK. It may be inferred that the positive relationship for VZK between CGCoI of Korea and PI of Korean products was caused as a result of the fact that the VZK sample may have greater experience and knowledge of eco-friendly policies and environmental regulation practices in Korea. However, VZV were found to formulate positive attitudes towards Korean products based on affective feelings of Korea's environment. It may be because VZV have not yet obtained enough information or experiences related to the pro-environmental aspects of Korea.
The current study results are expected to yield several academic and practical implications. Vietnam is attracting significant attention as a new consumer market for many multinational companies because of its rapid economic development and relatively younger average population [20]. Thus, it is very important for international green marketers to understand the reasoning behind the responses of Vietnamese Gen Z consumers towards the green image of country, brand, or product, as a result of Vietnamese Gen Z consumers being considered a promising green product niche market [31,36].
According to the study results, the CGCoI and AGCoI showed significant effects on GT and PI, but the impacts of CGCoI and AGCoI on GT and PI were different between VZV and VZK. The CGCoI and AGCoI of VZV were relatively low compared to those of VZK, and the GCoI was found to affect GT mainly through affective aspects. This means that despite a massive influx of Korean culture and products into Vietnam, the overall GCoI of Korea is not high, and therefore, it should be carefully considered when utilizing the GCoI of Korea as an international green marketing communication strategy in Vietnam. On the other hand, it was found that VZK have a relatively high level of GCoI towards Korea, which has a significant positive impact on GT and PI of Korean products. It might be the result of VZK having a higher familiarity of Korea and greater experience of the environmental policies and practices when they are residing in Korea. Therefore, the Korean government needs to raise the CGCoI of Korea through enhancing the Vietnamese consumer's cognitive understanding of the environmental advancement level of Korea using content marketing at the country level. Building a green country image of Korea can be an important foundation for Korea to shape a sustainable economic development model in the future, together with perceptions of advanced IT technology and excellence in popular Korean culture. Furthermore, companies should endeavour to enhance a positive green country image, as sustainable development goals (SDGs) are becoming one of the more critical global marketing strategies. Considering the high accessibility of Vietnamese Gen Z consumers to online communication means, it would be effective to increase the GCoI of Korea, as well as the GT and PI of Korean products by utilizing various social media platforms such as Facebook, Instagram, and Twitter. In addition, since Vietnamese Gen Z consumers are known to have a high interest in environmental issues, it would be an effective marketing method to enhance the green image of Korea and Korean companies by participating in environmental improvement activities in Vietnam or building partnerships with Vietnam's green companies.
Despite the academic and practical implications of the study presented above, this study has the following limitations. First, this study surveyed one university located in Vietnam and Korea, respectively. Vietnam is generally divided as three main regions, Northern Vietnam, Central Vietnam, and Southern Vietnam, and there are considerable cultural differences between regions [94]. However, the economic and time constraints prevented these differences from being accounted for in this study. Therefore, it should be considered that these geographical characteristics be factored into sampling in future studies. Second, this study did not consider the impact of product categories. This study was intended to examine the overall impacts of GCoI of Korea on GT and PI of general Korean products. However, it is likely that the impact of GCoI on purchase behaviour will differ according to various product categories. Hence, future studies may consider the impact of product categories on the results. Lastly, this study did not consider various moderating variables that could affect the relationships among CGCoI, AGCoI, GT, and PI for Vietnamese Gen Z consumers. Therefore, future studies need to consider various moderating or mediating variables such as NEP (new ecological paradigm), environmental knowledge, and environmental self-efficacy of Vietnamese consumers in order to provide more meaningful implications for the marketing literature and practice.