It seems that many people like to do bets in PvP. (Many are doing it already anyway) But if we have an official way to make bets in PvP, that would be very interesting for PvP and would boost the PvP players base.

A 1v1 room or box. Only 2 people can join. To start the match, each player has to put a certain amount of gold. There can already be options to choose from, or even better have people decide how much to put in the locked box. The box stays locked until the end of the game, until the highest score is reached by the winner. Then that winner gets all the gold that was put in the box by both parties.