Honestly asking for a friend.

He normally gets all the girls he wants but right now he’s dealing with a girl he dated a long time in middle school and they reconnected right now after high school. Seems the girl wants him for just sex but he actually doesn’t know as the girl is really good at hiding her feelings. She currently has a beta boyfriend and is currently cheating on him. My friend wants to know how he can find out if she likes him and if she feels the same ways. He told me he was just gonnna go up and ask her straight up how she feels and if she tells him if it’s all just for sex, then she’s cutting her out and becoming even more heartless. I told him that’s lowkey not a good idea, and I think there might be a better way to go about it. What’s the way to do it?