"You know her?"
Either 「の」, 「か」 or the combination of the two works. 「か」is a particle which turns the sentence into a simple question. 「の」could show a bit of doubt or demand of confirmation, and is also more likely to be used between close people. 「のか」is close to 「の」 but it ( especially its polite form のですか ) could be used to ask questions to a person whom you're not very familiar with.
Do you mean 敬語 (keigo : honorifics)? 警護 also reads keigo but it means "guarding".
The form ご存じる as a verb simply does not exist. We could use ご存じ which is a kind of adjective, which in this case would be something like あなたは彼女をご存じですか？