The men who are the most ATTRACTED to you and INTERESTED in you are often the LEAST confident around you.
We are all contextually confident.
We are very confident in some contexts and not confident in other contexts.
Having chemistry, attraction or being interested in someone creates chemicals in anyone's body that makes a person more insecure and less confident in that context.
This is why a man's interest or attraction doesn't mean he will pursue you. In fact it might mean the exact opposite.