Say, "I like you too, you are a really great guy and any girl would be very lucky to go out with you. But I only think of you as a friend and nothing beyond that. I also don't think that I am ready for a relationship in my life right now." Tell him to move on and there are plenty of girls out there that are so much better than you are. Let him know that there are too much things going on in your life at this moment and you want to put boys aside for now, and hope that he respects your decision.
Just let him know how you feel. Its not fair to make him think he has a chance.
If a guy like you and you do not like him be nice let him know gently. Treat him as though it was you who like him and he was not interest in you. Sometimes we can hurt a person and it can affect him for the rest of his life. You can simple say at this time in my life, I have other interests. Take care.
I would str8t up, and tell him, I'm sorry but I don't like you and I don't wan ta go with you. So COULD you kindly leave me alone and you ll just be friends
I'm going through the same thing and I think its just best to tell him the truth. Leading him on will only make you feel worse and regret yourself. Hope this helped good luck.
Say "plz plz don't take this to heart but I don't want to date you right now maybe another day lets be friends for longer( or for now either one) I want to date other people first( or I don't want to date anyone because maybe you got out of a bad relationship or something else)then when I'm ready I will tell you"
Easiest way is to tell him you don't want a relationship and to leave you alone ! Otherwise its grooming so go to the police !