1. Read The Gift of Fear by Gavin DeBecker. He explains how to sort out the bad ones before they cause you trouble. He is talking about avoiding serious trouble, like violence, but his tips on how to recognize bad men are excellent.
2. Consider talking to his previous women, if you can and if you have the nerve. Most of the time, they will be very glad to talk to you. Take his ex-girlfriend or ex-wife to lunch at a nice restaurant, one quiet enough so you can talk. This will tell you a great deal about what you need to know. Although there are certainly dishonest and vindictive ex-wives, most will simply tell the truth. And you can use DeBecker's tips and your own instincts to check out how angry they might be. If they are still emotional about him, you can take their story with a grain of salt. But usually, if they have gotten over him, they will tell you the simple truth.
3. Check out things he tells you. Many women are afraid to do this because they think that this would make them a bad person. And it's very unromantic because it might ruin your fantasies about him. But you DO have the right to check out statements made by a man who is not a close friend you already know but somone you are getting to know. Checking out what he says is one way of getting to know him.
4. If you are thinking of making any kind of a serious commitment (like being engaged or living with him or getting married or taking a long trip with him, or relocating with him, or giving him money or access to valuable property), have a complete background check done on him by a reliable investigative agency like Pinkertons. It will be a good investment. Lack of knowledge never did any individual or any love affair any good.
5. Learn how to let go of a relationship before it takes you for a ride and makes you crazy. Face the fact that MOST relationships do not work out. The withdrawal symptoms from a lost relationship can be very painful but they are not usually nearly as painful as what happens when you hang in there way too long.
6. Face the fact that women bond more easily emotionally when they have sex. It is purely recreational from a man's point of view, particularly a young single man. Consider being more conservative about sex than is today's fashion. Be self-protective. Don't have sex with a guy until the relationship has reached the point where you feel secure with him. And please read my story, "Girls and Boys Look At Dating Diffferently." .
Honestly i dont think you ever know, guys are mysterious.. If you want to be with him, be with him, but you have to keep your guard up bc lets face it, NOONE wants there heart broken....