The present study investigates the relationship between loneliness stereotypes and trust decision-making, as well as the underlying mechanisms involved. It consists of three experiments. Specifically, Study 1 examines the impact of loneliness stereotypes on trust decision-making. Seventy-two older adults were randomly assigned to either the stereotype activation group or the control group, where they read a paragraph of descriptive material before completing a trust game. Study 2 explores whether cognitive resources mediate the relationship between loneliness stereotypes and trust decision-making. Study 3 investigates whether emotional motivation serves as the underlying mechanism in the relationship between loneliness stereotypes and trust decision-making. The results show that loneliness stereotypes increase the trust levels of older adults (Study 1). Moreover, this effect is moderated by cognitive resources: adequate cognitive resources amplify the impact of loneliness stereotypes on trust, consistent with predictions of the motivational mechanism (Study 2). Finally, unconscious goal priming, as an intervention manipulating motivation, can effectively reduce the effect of loneliness stereotypes on trust decision-making. Specifically, after priming older adults' unconscious goals, the influence of loneliness stereotypes on trust was no longer significant (Study 3). These findings suggest that in the relationship between loneliness stereotypes and trust, motivations related to emotional significance may play a more crucial role. This study makes several theoretical and practical contributions. First, it focuses on the loneliness stereotype, a longstanding yet underexplored construct, thereby expanding research on the content of aging-related stereotypes. Second, it examines the relationship between loneliness stereotypes and trust decision-making, along with its mechanisms, enhancing our understanding of how negative stereotypes about aging influence trust. This also contributes to the fields of aging stereotypes, socioemotional selectivity theory, and dynamic integration theory. Finally, it offers valuable insights for future tailored interventions aimed at reducing blind trust among older adults in real-world situations.