Watch how he or she treats waitresses, employees, family members and anyone else he/she comes into contact with. Here is a rule that is rarely broken: Whatever problems you have before the wedding day, you will have during your marriage. The more you share, especially values, the better your chances of a good marriage. If you are basically happy, do not think for a moment that you can make an unhappy person happy by marrying him or her.
I promise you how the person treats others now is how this person will treat you later. It is exceptionally difficult to find the right person to marry. That is why it is so important to think through your decision by asking and answering critical questions. Do not think that marrying will solve any problem you have with the person. For example, if you think television watching is a form of self abuse and your prospective spouse loves watching for hours a day, you may have a big problem. On the contrary, the ability of the unhappy to make the happy unhappy is far greater than the ability of the happy to make the unhappy happy. How much of your love is dependent on the sex you are having?
It is a bad sign if the person you are thinking of marrying does not have good friends (including of long duration) of the same sex. This alone should rule out the person from consideration. It should go without saying that if the person is not kind to you, quit while you can. Yes, men are better at being distracted by work, sports, computer games, the opposite sex, and God knows what else, but it is not a good sign if you rarely miss her when not together. Having written a best-selling book on happiness and lectured on the subject on all seven continents, I am tempted write a book-length book explanation of just this question.
A woman who cannot hold female friends and a man who cannot hold male friends have issues that will probably sink your marriage. But it is far from sufficient that the person you are considering marrying treats you kindly. And what inner voice of doubt, if any, are you suppressing? As for women, if you don’t miss him, it is probably a really bad sign. Suffice it to say that the importance of marrying an essentially happy person cannot be exaggerated.
There’s no point in digging up dirt about her or stalking her on Facebook.