Unlike shallow people, a serious guy will give you sincere compliments. You will be able to sense a genuine praise from a fake one from a thousand miles away. He shows interest in getting to know you. When a guy likes a girl, then it is perfectly normal for him to show interest in getting to know her. He may ask you questions about yourself - what is your favorite color, things that you dislike, or the name of your first pet. If he is enthusiastic and lets you talk about yourself, then it is a definite sign of interest.
Also rich guys are probably older and just have more experience with women and a bigger dating pool. When I was working high school jobs, there was practically a silent army of older women around me who all had identical stories around that last scenario.
Of course, all of the above is brutally pragmatic and ignores the role of attraction, love, etc.
SOLD ~145 Bay 7th Street Single Family Home in Dyker Heights, Brooklyn, NY 11228
My husband and I are one of those college relationships you mentioned, and I would rather be dirt poor with him than financially comfortable with anyone else.