There are many ways women communicate, both verbal and non-verbal. Before social media and texting, most young men learned this through face-to-face interaction on a daily basis. Body language and tone of voice are very important. If a man is pursuing sexual contact with a woman he should at least understand the basics of how women communicate with men.
Ask your mother.
Ask your sister.
Ask your aunt.
Ask a female friend.
Ask your father.
Ask a guy who's been in a relationship for more than a 2 years.
They all probably know and if you aren't a complete dipshit they will probably tell you the truth.
Don't rely on advice from social media, celebrities, women's mags, men's mags, social justice warriors, dating sites, hook-up sites, porn ads, talk show hosts, star athletes, universities, wealthy men, exceptionally attractive men or the other guys trying to pick up drunken sluts at 2am.
Learn from people that know, not people that think they know.