how do you send diamonds to another player?

There's no way to directly send diamonds to another.

So you get the other player (the one receiving) to set up a trade in the currency exchange, selling 1 gold for the amount of diamonds you're supposed to sell them, for example 100 diamonds. You then go to the currency and buy that 1 gold for 100 diamonds (or whatever the amount is).

This prevents other people from buying your trade, since no one would want to pay diamonds for 1 gold, unless the intention is to "give" it away.

okay thanks