Those of you who like retold fairy tales may like this one. Or maybe not since the odds are good that you haven't read The Feather of Finist the Falcon. (Then, you can fix that. 0:)
But it opens with Finist having to deal with his lovely royal cousin Ljuba, out to magically seduce and control him for power -- somewhat complicated by being in the forest, where the leshy live -- and with Maria's father being slandered by a protegee, so that she, he, and her older sister barely manage to escape to live a wretched life on a peasant's farm, made all the more wretched by the sister's all but losing her wits in their distress and her fear of the forest and its "demons".
Finist stumbles on them there, and is instrumental in restoring them to life as a boyar and his daughters. And goes home to be wretched because of his magical abilities and her father's hatred of all magic. An adviser urges him to consider whether she agrees with her father, and he sets out to woo.
Unfortunately, her sister takes him as one of the forest demons, and Ljuba takes advantage of it to return to her plotting. There are considerably more complications before the end, involving a riddle game, an enchanted pin, a caftan stained with blood that can't be washed out, a return for a good deed, a monk who can become an eagle, bandits, and lots and lots of forest.