Want to leave this world full of troubles and pains. You can be a nun. You really want to become a monk.

This is an escape psychology. The world is a kind of exercise for yourself. What matters is your mentality. Otherwise, you will feel pain wherever you go. After becoming a monk, there will be many people you need to contact and many things you need to face. Don't think that you can escape all this simply by becoming a monk. What matters is what you think. Things are not the last step. At least you're alive!