Knowing - is a forever thing. You can never go back to not Knowing.
Knowledge is this abstract concept that can't be learned in a book; it has to be experienced and handed down from learned person to worthy apprentice. Knowledge is what happens when men and women transcend simple gender roles and become more complete.
She knows when she's not afraid to hold your gaze. When she carries herself with an infectious self-confidence. When she's not afraid of sex talk, she doesn't shy away from adult conversations, knows that the more spit the better, oral is always the fastest way to get him there, and she truly knows what pleases her, she Knows.
Generally, a woman is sensitive. Receptive. Caring. A woman Knows when she pursues sex like a man, wanting the orgasm, but appreciating the journey, like a woman.
A man who Knows is more sensitive than most. Not weak or submissive, just constantly aware of a woman's needs - how to touch her, how and when to kiss her, when to be firm and authoritative and when to let her take control. Having an orgasm is great, but not the most important thing.
Few women Know. Even less men do. Rarely do they find each other.
You won't Know until you see it, but once you do - you know they Know.