The Cursed Duke by Sandra Sookoo

Be careful what you wish for; it may just come true.

Miss Hannah Masterson is hopelessly on the shelf. Well past the first and second blooms of youth, and possessed of a curvaceous figure, she has grown weary of being bedeviled by her family about when she’ll wed. At her thirtieth birthday dinner, she blurts out something she can’t take back—the Duke of Steppingford has fallen madly in love with her and that they’ll be married within the next few months. No one need know she’s invented the bit of fiction.
Giles Fitzroy, 3rd Duke of Steppingford, has just returned to England from India. While reading the paper at breakfast, he spies an announcement telling the world of his engagement… to a woman fifteen years his junior he’s never met. Wanting to know who dared to put forth such gammon, he vows to crash his engagement ball, being held in a day’s time, and he will put Miss Masterson in her place with a dressing down she won’t soon forget.
However, the moment the duke sets eyes on his fake fiancée and hears her explanation for the bit of fiction, he sympathizes, but when he seals their fate with a kiss, everything changes. Now that Hannah’s make-believe duke has suddenly materialized, he’s keen to go along with the farce… and she isn’t. Through a busy week of forced proximity, the pair discover they have more in common than they thought, but can a no-name miss truly land a duke? Only they can decide.