There is only one way certain way to prove ownership, and that is by giving your PRIVATE KEY to that someone.
If we're strictly talking about
certain way to prove ownership, then even giving private key isn't enough. There are many cases where user tricked into download fake/malicious wallet where the theft could use it to prove ownership.
If you want to prove ownership of an address that has funds, you move the funds out first, and give out the private key, proving that at one point you possessed ownership of the previous address that had a balance.
Interesting idea, but it's not foolproof idea due to various hard-fork and claim altcoin with BTC address where there are people who buy & sell old bitcoin address.