oh and when you say "let's be friends" your leavong the door open in case you need him/her for something or so it wont be awkward if you run into each other later on. Most likely the person will never call to be your friend. But if you want to cut him/her off entirely avoid specifics. Bc if the person still really like you theyll find a way around your reasons. The simplest most generic sales talk proof breakup line is of course, "Im sorry we have no chemistry."

BTW dont do it over the phone or in an email or im. Thats the chicken shit way to do it. Be a real man or women and do it face to face.