The Warlord’s Lady by Eve Langlais

The warlord doesn’t believe in magic until he meets a very special lady.

Something evil is lurking in the mountains and Kormac doesn’t know how to fight an enemy that can’t be seen or touched.
While a warlord hates asking for aid, he can’t allow his pride to get in the way. He requests assistance from the witch queen—in secret, of course, because magic isn’t real. Or wasn’t in his corner of the world, until now.
Fionna, the witch who arrives to evaluate the situation, is unlike anyone he’s ever met. Bold. Fearless. Beautiful…
He didn’t count on how much she would test his patience—and his control.
As they work to squash the danger spreading from the mountains, and she impresses him with her skill and courage, he starts to wonder if she’s the lady he’s been waiting for. His mother certainly doesn’t think so, but Kormac didn’t become warlord by allowing others to make decisions for him.

However, taking her as his wife will depend on them surviving the machinations of the evil entity that’s returned to take its vengeance.