This is easy if you depositing Fiat, because you u can show them your bank statement,I mean my personal account in another bank.
Of course they will ask for a source of funds but I don't know the threshold which can trigger this compliance check. If you have a simple bank statement or any other supportive document it would be enough.
But with crypto is hard to explain to them!!
Because crypto is decenterlaized.. But If they mean the proof of my wallet, this easy to proof..