The development of mobile social networking service (SNS) triggers the growth of social commerce industry. Customers rely considerably on electronic word of mouth (eWOM) to make purchasing decisions. Thus, SNS is an important commercial platform that offers attractive opportunities and challenges to firms. This study sheds light on the role of SNS as a social commerce platform by focusing on WeChat, the most popular SNS in China. This study identifies three different types of trust based on SNS that customers perceive in the context of social commerce. These types of trust are contents trust, source trust, and platform trust. This study suggests the antecedents and consequences of each trust. Our results prove that eWOM intention relies on contents trust and source trust, whereas purchase intention depends on contents trust, source trust, and platform trust. This study also finds that contents trust is positively influenced by source trust and platform trust. Finally, the result verifies the key antecedents of each trust, namely, vividness and timeliness for contents trust, competence, benevolence, and integrity for source trust, and instrumental need and social need for platform trust. The discussion and implications on the findings are provided.