What does it mean for a man to tell you that he is hiding something?

If it's a relationship, there's something I'm not telling you.

If it's a husband and wife relationship, it means what happened.

If it's just friends, it means I want to ask you for help.

If you are not an ordinary friend, but someone who pursues you, there are some things you don't want to know.

If none of the above relationships exist, it means that you want to cheat you, such as money, health, or other things.