He is really a kind and gentle man and I know him 4 months ago and he said the he really likes me a lot but the problem is that we have different culture and belief. what should I say to him in a nice way that he will not get ofended. Because for me my. faith is my priority.
"No offense, you're a really great guy but I need a _____ *enter religion* man and I would never infringe upon your personal beliefs because that's disrespectful. So there's really no romantic future for us." Some messages are going to sting no matter how you phrase them so it's really just best to be honest and straightforward.
Just like that. Your faith is a priority and if he is to take you he has to accept your faith as well, and unfortunately you really can't accept being in a relationship with someone who isn't likeminded. It's going to hurt him because honestly if you felt this way you never should have gone out with him to begin with let alone four months. But honesty in this case won't be so bad.