We unconsciously sense 'matching' vibes from certain people. Some of it has to do, I believe, with a physical template. All these factors set off a signal in you. You were attracted. That's all there can be at this stage.
Women are very attracted to confidence as well as looks.
If a man exudes this, it is because he has what I call his sexual meter turned up. It is very very attractive. This is why women often fall for the bad guys. This is confident behaviour. Lot's of nice guys are confident too and we can learn to be wary at first, without withdrawing.