Doubting a person's attractiveness
I could see this is a pretty common theme. But usually, this kinda fear affects people who are actually in a relationship or marriage. In my case, I do find the person attractive and I know that and I don't doubt that, but I am doubting whether I find him attractive enough that I would feel satisfied if we were to have sex.
Re: Doubting a person's attractiveness
Well, in that regard it's not just attractiveness but also chemistry. And you really don't know until you go for it, unfortunately.
But the answer is mainly: you find him attractive. That's clear. What will you do if the sex is just bad? Is that a deal breaker for you or something you'd want to work on for the benefit of the relationship?