Hi and welcome!
You thank him very much for asking you, but tell him clearly that you do not feel that he is the one for you, so you are very sorry but you cannot go out with him.
Tell him that you hope he will soon find the right girl for him, but that it would be easier for you both, if he didn't ask you out again.
Good luck.
Try to be gentle ~ remember, he really likes you, even if you don't like him.
