In light of the current relevance of analyzing the motivational determinants of prosocial behaviors, an experimental design was applied to examine the influence of rejection sensitivity, affective states, and trust on prosocial behavior in the included versus excluded context. The research was performed at a Spanish university with a sample of 118 students. The results confirm that excluded individuals are more prosocial than included individuals only when they see reconnection as possible (hopeful excluded individuals). The inclusion/exclusion experience moderated (1) the links between rejection sensitivity and both affective states and prosocial behavior, and (2) the mediation of trust between affective states and prosocial behavior. Finally, a predictive model of prosocial behavior moderated by the type of inclusion or exclusion was partially supported. Results indicate the relevance of promoting different variables in included individuals, hopeful excluded individuals, and hopeless excluded individuals for prosocial behavior.