The Heiress and the Orc by Finley Fenn

She made a pledge to a wild, dangerous orc. And now he’s here for vengeance…
In a world of recently warring orcs and men, Ella Riddell is determined to ignore it all. She’s the wealthiest heiress in the realm — and soon, she’s to wed a lord, and become a real lady.
Until the night her engagement-party ends in utter disaster, and Ella runs for the forest — and straight into the powerful arms of a hulking, deadly orc.
And it’s not just any orc. It’s Natt. The orc Ella made a secret, foolish pledge to, many years past…
He’s huge and shameless and vicious, not at all the gangly, laughing daredevil Ella remembers. And he’s here with one shocking, scandalous aim: to wreak vengeance on Ella’s betrothed. With her.
With her hunger.
Her surrender.
Her undoing…
Ella knows she should run, even if this deadly enemy was once a friend. Even if his scent drags up a dark, forbidden longing. Even if his kisses are the sweetest, filthiest thing she’s ever tasted in her life…
But will Ella truly risk her perfect future, for an orc? Will she face the bitter truths of the past, and brave the terrifying Orc Mountain, before more war rises to destroy them all?