IIN I can't see if their pupils get dilated when chatting up women?

Ask her about herself to find where you have common ground. Once you have something in which you're mutually interested to talk about, you can relate experiences about stuff with humorous stories to make your opinions seem credible and your personality more interesting. Once you think you have this accomplished, then you look for body language and pupil dilation for signs of interest. At this point in the conversation either her attraction will be evident or it wont be. Subconsciously you'll know, its evolutionary psychology