How do you get rid of a persistent guy? AUGH, he won't stop!?

If you blatantly told the guy to leave you alone, don't write me any more, I am NOT interested in you at all, I would agree about warning him that your next option would be a restraining order, harment charge, maybe even a stalking complaint or some other kind of legal action. Hopefully he will get the point you don't like him. Then if he is stupid enough to persist, actually file the complaint.