This study aims to analyze how trust in the seller mediates the relationship between four levers of digital interaction—effective use, intention to use, perceived ease of use, and seller reputation—and purchase frequency in e-commerce environments. To this end, four mediation hypotheses are proposed, in which trust in the seller acts as an intermediary variable connecting each antecedent with repurchase behavior. The research adopts a quantitative, cross-sectional design based on data collection using structured questionnaires administered to a sample of 316 people in Peru. The study participants are male and female frequent users of e-commerce platforms who provide information on their actual usage behavior, cognitive predisposition, site usability evaluation, and perceived seller reputation. Data are analyzed using structural equations in specialized software, assessing reliability, validity, model fit, and indirect effects via bootstrap. The results show that the model explains 63.2% of the variance in seller trust and 64.0% in purchase frequency. Seller reputation has the most significant indirect effect on purchase frequency through the model. The most important conclusion is that seller trust constitutes the central mechanism that translates reputation, practical use, and intention to use into more frequent purchases. These findings emphasize the need to enhance reputation and user experience strategies to strengthen trust and increase repeat e-commerce transactions.