OK, wait, wait, wait. I've conveyed the wrong message here. He isn't harassing me. He just wants me to go out with him, which isn't going to happen. And he keeps finding new ways of asking, which is annoying.
So, I'm looking for the most final "no" I can find, that doesn't get me in trouble. Thanks for any and all advice.
From the description he is harrassing you. That's what the word means. Admitting it might help you solve the problem. I don't know how to say this nicely, but victims worry about getting in trouble when dealing with these situations. Getting in trouble by being open and loud about it will at least have other people watching what is going on. Janet had good advice.