I know not
A way of saying you totally get what the other person is saying. Usually said with extra emphasis on the word 'know' like you're trying to prove a point.
"I KNOW NOT WHAT YOU MEAN!" (said by a kid who got confused by a simple question.)
"I KNOW NOT THAT YOU'VE SAID THAT BEFORE!" (said by a kid who heard the same thing for the third time.)
"I KNOW NOT THAT YOU'RE TALKING TO ME!" (said by a kid who thought they were being ignored.)