Questo and Hocoin were giggling at the side of the corner when they saw the ultimatum of the duel. Against their peers' advice, they decided to go through the bet by putting a huge sum of money onto Jin's side since the odds were heavily against them.
In turn, when the duel outcome came about, they won a ton of money that could effectively buy a rather huge house in the Noble's quarters. (Hocoin was able to buy 10 of such houses from the winnings) That was how much money they were earning just by betting on Jin's now commando mages. It was a good thing as well since now they have some funds to pay the overtime for the people who had been working hard for them. (After all, Hocoin did tell Questo to use his guild's funds as part of the betting money. If anything, Hocoin would put up his savings as collateral if things go awry.)