"Let's JUST be friends... and I make it a rule no a commandment in my life that I never date friends" If he persists, ask him if he has met the local beat cop personally. One more word, and you will see to it that he does. If he's on your property. order him to leave (hopefully with witnesses) and then call the police to report it. If he comes back, since they have the report, he will be charged with criminal trespass which is MUCHO serious compared to simple trespass
If its on the phone, tape it and explain clearly that you do NOT want him calling you and if he persists you will charge him with harrassment. Then notify the phone company so they will be aware.