I think I can usually spot kind of a innocence right from the posture of women. I mean, the kind of people who are kind, sincere and honest but who don't make a number of that. And when I spot that, there's a good chance that I also get romantically interested in the woman.
Another thing that I have been thinking about that I think somewhat relates to the subject is what really makes you have a crush on someone. My theory is that feeling "chemistry" with someone is usually connected to exceptional mutual understanding of non-verbal communication. I mean, most of it is usually misunderstood even though you may get a strong sense of the other person but still there are times when the non-verbal communication and reality just happen match exceptionally well.