no no im honest
i can give any one in usa up to 20 btc for every one
paypal account i will take it because if every one can not pay my btc in time i will use it as collateral
it is my address
3Gdk8rHYXuFYV4YsMcg9vmZ9NxdaUtAGem
Sure it is!
Then you won't have any problems signing a dated message with that address and letting a trusted escrow hold any collateral.
If you can't sign because it's a multisig address then temporarily move the coins to another address and sign a message with that one.