The Duke of Aces by Rachel Ann Smith

Wagering on Love is Risky…

A lady’s fate should never be determined by the turn of a card.
Lady Isadora Malbury must remain unwed if she wishes to continue to be a member of the exclusive and secret Wicked Ladies Salon. Having survived two Seasons already without a single proposal, one more shouldn’t be a challenge, that is until she finds herself wagering with the pompous Duke of Aces for her hand.
Love is not in the cards for one of England’s top spies.
The Duke of Avondale has decided it’s time to wed. As an agent for the Foreign Office, he needs a woman who can keep a secret. Spying the reserved and aloof Lady Isadora at his summer house party, Avondale believes he’s identified the perfect candidate to become the next Duchess of Avondale. Except, the woman has no interest in marriage, but she does have a fondness for taking risks.