Attitude similarity effects on attraction seem to be mediated sequentially by positive affect, inferred attraction, and trust. That is, the first two mediators influence each other in building trust, which is translated into attraction. However, because the mediators and attraction were measured responses to attitude similarity, the correlational nature of data precluded definitive conclusions about sequence of the mediators. Further, a general model of attraction denies any causal role of positive affect. In this experiment, therefore, the authors manipulated (a) positive affect and (b) the partner’s liking for the participant, and measured trust before attraction. As predicted, positive affect moderated the partner’s liking effects on trust and attraction, and the interaction in trust mediated the interaction in attraction.