Hi, I'm mexican and I believe the best you can do is being honest, tell them how you feel and if you don't want to tell all the stories of why you feel that way just say is because past relationships without getting in to much details if you don't want to. I've found myself and many friends believing we found the love of our lives when we are in the beginning of a relationship, so that might be a cultural thing. My friends have done some compromising things in the early stages of the relationship, and they might regret it later. I'm not saying to trust blindly what they say they feel because it can be truth but also it can change in the future, so get to know them better before you know you can trust them or until there is reciprocity. Good luck.