I know not - A fake way of agreeing with someone, usually said by someone

A fake way of agreeing with someone, usually said by someone who is being lazy or doesn't care about spelling or grammar.

"I KNOW NOT WHAT YOU SAID, BUT I KNOW NOT WHAT I MEAN." (said by a kid who didn't know the difference between 'their' and 'there'.)

"I KNOW NOT THAT YOU'RE TRYING TO CONFUSE ME." (said by a kid who didn't know how to spell 'confuse'.)

"I KNOW NOT THAT YOU'RE SMART." (said by a kid who didn't know how to spell 'smart'.)