In the last few years, the number of Internet users in Indonesia was growing rapidly as many people started to use e-commerce sites. Utilization of C2C e-commerce in particular has a risk that may reduce people interest in online shopping. Of the many factors that may influence online shopping intention, trust becomes the key. This study built a model to explain the purchase intention in the C2C e-commerce environment. In the model, buyer's trust to the seller is a major factor that influences the purchase intention. Cognitive trust and adoption of e-WOM information is used as a factor that explains how trust is formed. We tested the model by distributing online questionnaires in Kaskus forum, the largest online shopping community in Indonesia. Total 114 valid questionnaire responses were used for analysis. The analysis was conducted using PLS and Smart PLS 2.0 as the tools. Our results showed that trust have a positive and significant effect to the purchase intention. Later it was found that two cognitive trust variables, the perception of ability and integrity of the seller, along with the adoption of e-WOM information have a positive and significant impact on the trust to the seller.