A Promise of Fire The Kingmaker Trilogy 1

"Cat" Catalia Fisa lives disguised as a soothsayer in a travelling circus. She is actually an exceptionally powerful Magoi - known as the Kingmaker - who can divine lies. But Cat has no interest in using her powers - or in being used for them - and stays under the radar, far from the clutches of her power-hungry homicidal family.
An ambitious warlord from the magic-deprived south, Griffin, is intent on bringing peace to his newly conquered realm. When he discovers Cat is the Kingmaker, he abducts her - then does everything he can to coax her to help his people willingly.
Cat has worked hard to avoid the dangerous destiny she fears is in her blood but the balance of power in their world is shifting. The old magics are no longer all-powerful and there's a new, ferocious force at work. To survive, Cat will have to explore the true depth of the powers she's spent so long running from - and perhaps even learn to work with her enemies . . . .