I think debonair implies that the individual is self-confident, in a good mood, outgoing, potentially good company.

I would have to say well dressed and with a confident attitude.
Attitude is so much, isn't it? We've all known--or been--kids who wore exactly-right clothes and were still outcasts. If only we could tell them. If only I had known.

I've seen beautiful wall flowers, alone just for lack of
a smile.