Most Helpful Guy
Here's my opinion on the way to do that. Try to have conversations with him about things that have nothing to do with sex. Talk about your likes and dislikes (food, music, entertainment, etc.). Talk about your families. Talk about your ambitions and things you'd like to do some day. Go on a few dates (at least 3, preferably 5 or even more).
If the guy only wants to get in your pants, he's probably going to find all those other topics boring and won't seem interested in your thoughts and feelings and might even stop pursuing you. If he cares about you as a person and not just a female body, he'll like finding out more about you and he'll remember things you tell him and see eager to learn more.
By the fifth date, you should have a pretty good idea of how interested in you as person he is and how well he treats you. There might be a few guys that can bluff their way through all that and fake interest in you just to get in your pants but I think most will fail that test unless they really truly care about you as a person in addition to wanting to have sex with you.
My personal opinion is that having sex on any of the first three dates is a mistake because then sex becomes a basis of the relationship when mutual respect and an emotional connection should be the basis, with sex as a wonderful addition to that.