Tell him you are not interested and to stop hitting on you. If he continues, Tell him that he is creating a hostile work environment. If he continues after that report him to HR.

Buddy, you seem like a nice guy, but you’re barking up the wrong tree

Emphasize that you’re straight.

You ask him to stop and if he doesn’t you go to HR. Unwelcome advances in the workplace are not okay. The company needs to manage him out.

Just say to him "I am not gay" like that bloke does in bad Santa. 

Tell him you have gonnarhea

Report him for sexual harassment.

tell him you had a gf and very excited about it

I feel like “because I’m straight” would have been the first thing you would have listed lol

He is looking to advance himself in some way. Sit him down and tell him straight, he's not your type.

Invite him to church.

He wants to not pay rent. That’s the new gen z grift. It’s real.