The Healer's Apprentice by Melanie Dickerson combines two main elements: religion and fairy tale.
The fairy tale aspect is swathed in the book's historical atmosphere. Set in a time when invisible demons were an all-too-real fear of the common man, Dickerson forgoes evil fairies and sets us up with a sorcerer who can commune with demons.
I can't help but admire Rose's devotion to her faith. A character needn't believe in God for me to like him or her, but I do like to see characters trying to remain true to their beliefs. The best example of this I've ever seen is The Blue Castle by LM Montgomery (of Anne of Green Gables fame), where the main character comes from a religiously and socially oppressive background and rebels in a way that scandalizes her family but maintains her beliefs and honor. In The Blue Castle, Valancy doesn't wake up and realize everything she's ever been taught is wrong. She realizes she hates her situation, and she changes it. It's empowering.
Alas, The Healer's Apprentice is no The Blue Castle. Though Rose shares a similar core of honor with The Blue Castle's Valancy, Rose never quite gets the courage to change her situation. It is partly Apprentice's plot itself, as a fairy tale adaptation, which keeps Dickerson from exploring that theme to a satisfactory depth, but it is Rose's continued lack of action that keeps her from achieving the height of admiration true heroines deserve.
Dickerson uses Rupert as a source of conflict for Rose, but his wooing of her is slow and takes up a disproportionate amount of the book's length for the little conflict he's able to provide. The entire Rupert affair would have been far more messy (and interesting) if the leading man weren't out of town the whole time.
In the end, I felt that the story had two plots that were battling each other for supremacy. The plot of Rose's feelings for the two brothers and how her faith affects her struggle to deny one and accept the other, and the plot of Lord Hamlin hunting the evil sorcerer who threatens his unknown bride. Alas, not enough happens in either plot until closer to the end.
I wanted to see more danger and action and Lord Hamlin, and I wanted Rose to have more chances to act and affect her own life.