This study centres on the Idle Fish platform, a prominent online marketplace for second-hand goods in China, and constructs a theoretical structure predicated on social cognitive theory and social capital theory. The quick expansion of the sharing economy has not merely catalysed economic transformation but has revolutionized consumption patterns. This research employed a survey methodology, utilizing a digital questionnaire disseminated via Credamo, which yielded 400 valid responses. The sample pool on this platform is of exceptional quality. Prior to accessing the questionnaire, the respondents must complete five perquisite prompts, which ensure their attentiveness. This procedure acts as a safeguard, ensuring the high calibre of the data collected. Employing the SmartPLS (structural equation model), the paper elucidates how self-efficacy and social trust, influenced by social referral, system quality, platform resources, community interaction, rights protection, and shared goals, drive users’ sustained willingness to utilize the sharing economy platform. The findings reveal that self-efficacy and social trust positively impact users’ willingness to persist in using the platform of the sharing economy. Furthermore, shared goals emerge as the most critical determinant of social trust. The paper accomplishes this by discussing the practical suggestions of the research findings for the platforms of the sharing economy.