There is literally nothing you can say to him that won't convince him you aren't sexually attracted to him. In fact, you don't even have to say anything - you just are. It's science.
Mystery is for us normal single guys what Sarah Palin is to the Democratic Party. He has dedicated his life to looking like a raving moron so that others may look smarter by comparison, and therefore, justify his own existence.
Vagina, that rarest of artifacts, more legendary than the Hand of Vecna. It is the object of entire LARP campaigns. And like the One Ring, as soon as you've slid it on, you spend the rest of the week trying to lose it in a volcano.
This guy sure is concerned about men talking to him or looking at him or touching him. REALLY concerned. Seems to be on his mind a lot. He mentions it often. Very often.