OK, I'm going to be nice and give you practical instructions.

1. When you like someone, pay attention to what that person says and do. We are taught to offer soft rejections. So a rejection would look something like "You are a nice guy but [insert reason for not wanting to date/be with you]".Or but we can be friends. That means she doesn't like you romantically. Maybe as a friend and only a friend. So believe it. Now you might have been conditioned by other men to ignore it and don't believe what the woman you like is telling you. That is disrespectful to her. And being disrespectful would make you dislike you more or stop liking you as a friend if you are friends. So believe her.

2. So rejection is hard, we get it. We also get rejected. Here women are taught that it is somehow their fault. We are not pretty enough, not nice enough, too much of something or too little. So supposedly we need to change until that person likes you. And men are taught that women should like then so they need to insist. Wrong. The other person doesn't like you and the reasons are irrelevant. If you are happy with yourself, then what you need to do is to accept that it is not meant to be. And that you need to keep looking for someone that you have mutual attraction and liking.

3. So you have been dumped and hurts. Then be nice to yourself. If you can, buy yourself nice things. Take time to do thing that you enjoy and make you happy. Try a new hobbie and surround yourself with people who love you like family and friends (but not the person who rejected you and wanted to be only friends).

4. When you already feel better and good in your own skin, try again. Meet new people, go out and pay attention to the people who can appreciate your little things. The one who understand why you spent hours painting miniatures or hiking. That person who you might have connection. Maybe it won't work out either, but as long as your treat people with respect, you would end surrounded by people who love you. Friends can be as satisfying as lovers. And you should have friends even if you find a partner.

But accepting that things usually don't go as planned is a basic life skill that applies to everything. Studies, work, love... Sometimes you just need to accept that something is not going to happen to start looking into other possibilities (that might even be better than the original). That is basically life and we all are learning how to live it.