Attitude similarity-a cause of attraction--and the partner's trustworthiness--a mediator--were manipulated at two successive occasions, and trust and attraction were measured. Because the partner's trustworthiness was known at Time 2 only, attitude similarity influenced the initial trust and attraction responses and the final trust, but not the final attraction. This experimental evidence for mediation by trust was further confirmed by a modeling of the final attraction on the two manipulations and the three previously measured responses. Specifically, the initial trust and attraction responses originating from attitude similarity bolstered the corresponding responses to the partner's trustworthiness but the initial attraction did not influence the latter trust (i.e., no reverse-causation). Results solidified the previous evidence for mediation of similarity effects on attraction by trust.