How to look at a person's personality in daily life?

What is a person's personality? You can see it from his attitude towards his friends. If he really wants his friend to be good when he is in contact with him, then this person's character is still good. But if you associate with a friend, he has been hiding something. On the surface, he hopes that the other person will be fine. In fact, when he sees that the other person is fine, he will be jealous. If a person has these behaviors, he will be jealous. At the beginning, I had a very nice person, and I regarded him as my brother. I thought it was the same for me in his heart, so I would tell him what was on my mind, and I told him not to tell anyone about it. But what I didn't expect was that after I told him with my front foot, he told someone else with his back foot, so it was said that this matter spread from 1 to 100, and most of them were. Later, I found out that he told me the secret. These are all my sad things, but we didn't expect him to base his happiness on my pain. Since then, I have never contacted him again. What about a person's personality? You can see it from his attitude towards his friends. If he treats his friends sincerely, then you can see that this person can communicate.