Can't believe him? please help me...?

I think you should keep trying to get to know him on a friend level for a little while longer so you can try to decide for yourself if he seems like a genuinely good guy or not. If he seems like he enjoys hanging out with you and talking to you and doesn't just talk about how he thinks you're pretty of wants to kiss you or things like that then I think he is probably not just after sex. If after talking to him more you think he seems like he really likes you then I think you should definitely go for it. Don't worry too much about having your heart broken, it is bound to happen sometime in life and you can't avoid all relationships because of it because then you would miss out on a lot of good experiences. Just try to get to know him and have fun :)