Bet (ベット betto) is a keyword that appears on ARTS and spells. By spending a specified number of coins while using ARTS with Bet, one may use additional or stronger effects on that ARTS.
In Lostorage incited WIXOSS, Selectors can bet their coins on special abilities, ones that directly act on the opponent instead of affecting the cards they have. Examples include Ril's Honest, which forces the opponent to tell the truth, and Mel's Berserk, which incites the opponent to attack. Using these gives great advantage in battle, but if a player who bets loses, they lose an additional coin for each time they bet.