As reported by an experiment, "resemblance to the subject's own face raised the incidence of trusting a partner".
The subjects were asked to act as the receiver of money for several rounds to ensure realism.
[1] Facial resemblance does not only enhance trustworthiness, but also increases the chance of prosocial behavior.
One theory is that this prosocial behavior occurs because facial resemblance is a potential cue of kinship.
The results conclude, "Though an individual may be viewed as more trustworthy, the effects of resemblance on attractiveness are lower.