A Duke's Wild Kiss (Kiss the Wallflower #5)
Tamara Gill

Jasper Abraham, Duke Hamlyn, did not think his Season would be taken up with helping a bedeviling chit in gaining her revenge. Everything would work out splendidly well if he hadn’t already agreed to help his friend keep Olivia away from him during the house party and remaining Season.
Thrown together with opposite goals, Jasper cannot help but wonder why anyone would overthrow the delectable, sweet Olivia Quinton. Playing her fake beau is no chore, and the more time he spends with her, the more he wants to do a lot more than flirt with the chit.
Unfortunately, when games are played, there can be only one winner, but perhaps in this folly, everyone will lose.