The Twisted Throne by Danielle L. Jensen

"A commander who bled to defend her people, Ahnna is haunted by two beliefs: The first is that she failed to protect Ithicana from invasion. And the second is that saving her homeland means leaving it behind forever. The Maridrinians left Ithicana in ruins and its people impoverished. So when the wealthy kingdom of Harendell claims Ahnna as a bride for its crown prince, she is prepared to do whatever it takes to gain influence as the future queen--and to control the gold that comes with the throne"