See how he treats his mom. This is a test of how he thinks of women in general and what habits he has around them. Possibly even better, See how he treats the less popular people. This will test his selfishness level and that is a BIG plus for long term happiness and honesty. If he thinks of others more than himself, he is a winner and you will enjoy being around him.
Going off of what hamath said, see how he treats the people around him. See how he acts in different circumstances, who he hangs around, and how he talks to people. If you like how he acts, and you think he's a good guy, talk to him and become friends. While you're friends, continue to watch him. See if he acts the same way you thought he did. If he truly is good, then he's worth it. I hope it works out! Good luck!