I can give you 0.5 btc if you promise to return 1 btc in one week.

If you agree please send me your address

I WOULD BE HAPPY IF YOU CAN SEND SOME HERE: 1Fder72y9qTjWuPqwWojXKt9BEz187R7Zh

Of course. Please say this:

"I promise I will return 1 btc for the 0.5 btc within one week."

Once done, I will send the bit coins.

I promise I will return 1 btc for the 0.5 btc within one week