Dance of Thieves Series ( Dance of Thieves, Vow of Thieves) by Mary E. Pearson

At the same time, Kazi, a legendary former street thief, is sent by the queen to investigate transgressions against the new settlements. When Kazi arrives in the forbidding land of the Ballengers, she learns that there is more to Jase than she thought. As unexpected events spiral out of their control, bringing them intimately together, they continue to play a cat and mouse game of false moves and motives in order to fulfill their own secret missions.

Mary E. Pearson's Dance of Thieves is a new YA novel in the New York Times bestselling Remnant Chronicles universe, in which a reformed thief and the young leader of an outlaw dynasty lock wits in a battle that may cost them their lives—and their hearts.