rape?

xxx
If two people are drunk should it be considered rape? Even if neither remembers? What about regretting it the next day? Why do we say a woman isn't of sound mind to consent but the man is supposed to be of sound mind to consent and understand but since the woman can't understand either then why is she not held accountable too?
I'm not talking when someone is passed out or other obvious rape here. 
Also why do we so quickly assume all accused are guilty? There have been girls who accuse a man cause they don't like him. Yes it's rare but if there's literally NO evidence he isn't guilty.