How well do you know your friends? Or your colleagues and acquaintances?

If you are looking for sincerity in relationships, then the above questions become important. This is because your perception of a person makes you either comfortable or cautious around them, and your perception can be right or wrong. If you do not know a person well enough, you may disclose things to them that may be used against you. To have a mutually beneficial and fulfilling relationship with someone, you need to be sincere in wishing them well and giving them advice. In turn, you should be able to expect the same from them.

So, how do you find out a person’s true character? The second caliph of Islam, Umar ibn al-Khattab, gives us three ways of doing so:

“You don’t really know a person until you live with them, travel with them, or do business with them.”

1. Living with someone.

This is about as personal as it can get. You can see his or her eating and sleeping habits, cleaning habits and how he or she function in a private space. Seeing a person from this close allows you to connect on a deeper level.

2. Traveling with someone.

One of the main consequences of this is that you get a taste of a person's tolerance level. How patient is this person? How willing is he or she to compromise in a difficult situation?

3. Doing business with someone.

Money talks! And so do those who have it. Sometimes business conflicts can turn ugly; they can show you what a person truly values. If not a business partnership, then any regular work setting can present different scenarios for you to evaluate. You discover peoples’ ethics and integrity, or lack thereof.

When you observe how people behave and interact with you in the above scenarios, it teaches you how much to disclose to them. It gives you the knowledge and the confidence to trust that person and add him or her to your inner circle. And on the basis of that confidence, you can foster that relationship to grow into something more fruitful.

While you may be able to pinpoint good or bad qualities about a person, based on one of the above situations, don’t be deluded by a single instance of good or bad behavior. Don’t jump to conclusions like, “This person is so stingy!” or “She is the most perfect person I’ve ever seen!”

People are not binary; rather, they are complex -- shaped by a myriad of positive and negative experiences -- just like you. They have good days and bad days. These things shouldn’t cause you to label them, because that is simply not fair.

Going back to the purpose of this article, it is important to evaluate peoples’ interactions with you over time if you want to know how sincere they are. By this standard, consistency is key. A single instance of good or bad treatment does not make a person sincere or insincere towards you; rather it is a combination of factors, a pattern that emerges in different situations, that tells you whether or not someone is a keeper.