I would like to think just based upon my own actions when out and about. If we are into you/someone I think it is often pretty obvious by our actions or often pretty forward signals, especially if we are just looking to get dicked downright quick like most of us are. IMO, if a woman is not very readable with her communication with you, she either isn't that into it, perhaps more shy even trying to go about it or she just is not interested which should be pretty obvious as well. I do not think it is rocket science to know if/when a woman wants to hookup with you.