Blows you off means she doesn't want to date you.It can even mean she doesn't show up to a date. http://www.urbandictionary.com/define.php?term=blow+off A "flake" is an unreliable person,someone who is a bit out of touch with reality,maybe even a bit crazy http://www.urbandictionary.com/define.php?term=flake

Something to remember... we never say "what means" in English when talking about definitions. That's completely unnatural. We would ask the question in one of two ways: 1) What does "a woman blows you off and flakes" mean? 2) What's the meaning of ""a woman blows you off and flakes"? To blow someone off is to reject someone. Think of blowing away dry leaves. It makes the other person seem very insignificant and unimportant. As Ruthi has said, the rejection can come in the form of not coming to the date you've arranged, in which case she also "stands you up". "To flake" is to not keep your promises or commitments, specifically your presence at an event. If she doesn't turn up to a date, you can say she flakes. I also agree with Ruthi that you need to be very careful when you use slang phrases - it may sound wrong or inappropriate or even rude, or people might just think you speak English in a funny and unnatural way. You really need a specific context to use slang. It's better to focus on regular English, which is really what native English speakers use anyway.

I forgot to mention that these are SLANG expressions and you would not usually use them in writing,certainly not in official writing for a teacher or for an exam.