Winds of Courage by Melanie Cellier

Delphine possesses great power—too much power for the daughter of farmers. The Mage’s Guild would eagerly take her, but she wants nothing to do with its arrogant and self-centered members. That is, until her friend is abducted in front of her.
Now Delphine needs her power, but to access it, she’ll have to apprentice herself to a traveling master. Amara is willing to take Delphine, but Delphine has a secret—one that will cripple her apprenticeship before it even begins. And once she leaves home, the secrets keep mounting.
On the road, Delphine’s healing power wins her a new friend—a wild fox she names Ember—but it also catches the attention of the dangerous man who abducted her friend, and of Nik, the mysterious mage hunting him. Now Delphine herself is in danger, and Nik might be her only way out. But first she has to overcome her crippling secrets and convince Nik that together they can be stronger than apart.