Self-compassion, as a personal psychological resource, has been proved to play an important role in coping with suffering. Based on self-determination theory, the present study attempts to establish that self-compassion can promote trust, and the sense of interpersonal responsibility mediates this relationship. Study 1 used cross-sectional data in a community sample of 322 adults to reveal that self-compassion was positively related to trust, and the mediating effects of the sense of interpersonal responsibility were significant. Study 2 used the latent cross-lagged panel model among 1304 college students at three-time points set at six-month intervals to replicate the results and proved the longitudinal mediating effects across groups. Finally, a casual chain design was used to test the mediation effect in Studies 3 and 4. The results indicated that self-compassion induced by writing task resulted in a sense of responsibility in Study 3 (N = 145), and the manipulated sense of responsibility promoted both trust behaviors and beliefs in Study 4 (N = 125). Through four studies, this study highlights a novel but unexpected viewpoint that treating oneself in a self-compassionate way can not only help individuals cope with various challenges but also motivate them to obtain interpersonal benefits. These findings can help motivate community workers and mental health researchers to increase social capital by focusing on self-compassion and interpersonal responsibility.