Social and economie exchanges often occur between strangers who cannot rely on past behavior or the prospect of future interactions to establish mutual trust. Game theorists formalize this problem in several “one-shot” game – such as the trust game - predicting noncooperation – since the investor is not expecting trustee to reciprocate it is not rationally to invest. Bohnet and Zeckhauser (2004) suggest that, due to betrayal aversion, people seek to avoid situation in which one could be betrayed. We argue that this behavior could emerge also due to regret aversion.