I can already smell fish. Why would a casino ask a player that is about to make some withdrawal about source of wealth or income. Of course your source of income should be the money you are about to withdraw from them  I mean I don't know what right they have to ask that where you already have some cash with them to withdraw. They would have asked that during KYC if they suspect money laundering but it is not just about when you want to withdraw.

You could drop the casino identify so users can know how trusted they are and if they are just honest with their request.