With the advancement of ICT, consumer-to-consumer (C2C) services have been rapidly expanding, encompassing both personal skills and goods as shared assets. However, disputes arising from differences in user expectations and transaction perceptions have been frequent. Therefore, in C2C Services, the information provided by transaction partners serves as a crucial criterion for Trust Formation in purchasing decisions. This research aims to characterize the display information on platforms and identify the seller-side display information that enhances trust. To this end, we extracted screen-displayed information from current C2C Services and classified display information based on the trends of the extracted elements. Next, a ranking experiment using conjoint analysis was conducted to identify the optimal combination of displayed information. As a result of the analysis, we classified the services into three categories based on the subject of the transaction. It was also confirmed that the display information emphasized by each service group differed. Additionally, it was observed that prior experience with service use may influence the information trusted and the purchase decision-making process. On the other hand, as an overall trend, buyers tended to place greater importance on information about the seller rather than on the product itself. In particular, information regarding the seller’s characteristics and personality was recognized as a key factor in reducing anxiety and fostering trust. This result is considered a valuable indicator for determining appropriate display information in the UI design of C2C platforms.