The Duke’s Twin by Lauren Smith

Rebecca Livingston has a problem: Her mother is desperate to marry her prettier, more talented, younger sister Lydia, off to the handsome Duke of Wiltshire but when Rebecca and her family arrive at the grand ducal estate it’s Rebecca who falls right into the handsome arms of the duke himself. Rebecca tries to avoid the seductive duke but neither she nor he can keep their hands off each other.  Her mother is furious, her sister is thrilled for her – but can it be possible that the duke wants Rebecca as much as she discovers she wants him? 

Miles Beresford has a wicked reputation, but will do anything for his twin brother Justin, the Duke of Wiltshire. Even if that means assuming his identity for a week to suss out the intentions of some young marriageable chits fresh from the London season. But when Rebecca Livingstone stumbles out of a coach and into his arms, he realizes that he might be in serious trouble – and that playing an imaginary duke to win her over may be slightly over his head. Does Rebecca love him or the dukedom, and can he bear to lose her if he admits he’s just the Duke’s Twin?