The Magic question you must ask at the end of the interview is.
“Is there anything about me that holds you back from offering the position?”
It is magic because if there is anything on their mind you have just given them the opportunity to bring it up now and you will get a shot at dealing with it. If you don’t a negative thought will fester and they will not offer. It is also magic because the later part fop the question presupposes they are considering offering you. The whole question of course shows you are keen and everyone wants to offer someone that is keen to work for them.