WhatI have read on these cashiers check scams is that it takes weeks to figure out they are bad and you are left holding the responsiblity.. Never,NEVER release a vehicle without clearing the funds first. Most people whom are honest will understand.. The folks who want to scam you will want the vehicle right now. If she is wanting a copy of the check its more than likely authentic. but beware there always is a scumbag looking to screw you over.