The traitor's kiss / Erin Beaty.

Enhanced descriptions from Syndetics:

An obstinate girl who will not be married.
A soldier desperate to prove himself.
A kingdom on the brink of war.

"An action-packed, expertly plotted story, drenched in double crosses and intrigue, with an irresistible heroine and a sweet and sexy romance." -- Publishers Weekly, starred review

What makes her unfit to be a lady, makes her a brilliant spy--but can she spot another?

With a sharp tongue and an unruly temper, Sage Fowler is not what they'd call a lady--which is perfectly fine with her. Deemed unfit for marriage, Sage is apprenticed to a matchmaker and tasked with wrangling other young ladies to be married off for political alliances. She spies on the girls--and on the soldiers escorting them.

As the girls' military escort senses a political uprising, Sage is recruited by a handsome soldier to infiltrate the enemy ranks. The more she discovers as a spy, the less certain she becomes about whom to trust--and Sage becomes caught in a dangerous balancing act that will determine the fate of her kingdom.

With secret identities and a tempestuous romance, Erin Beaty's novel, The Traitor's Kiss , is a classic story with an espionage twist.

An Imprint Book

" Marital and martial matters collide when brides and spies become ensnared in a treasonous plot . . . . Sage is a clever, contrary female protagonist who remains realistic and likable, while her fellow protagonist Ash is enigmatic enough to require a second read. . . . Both epic and intimate, a semi-old-fashioned alternative to the wave of inexplicably lethal superheroines and their smoldering love triangles. " -- Kirkus Reviews