Rosemary and the Fairy King

Rosemary is the seventh daughter of a seventh son. Unlike the life of adventure and glory a seventh son of a seventh son would be destined for, Rosemary is destined for a life of drudgery and chores. The only hope she has of a brighter future is marrying somewhat well, like her oldest sister.
But Rosemary has always held out hope for a special destiny.
That is why, when one of her sisters disappears with a creepy stranger who claims to be a matchmaker, Rosemary takes it upon herself to journey into the dangerous forest to find out the truth.
But the truth she finds is even worse than she imagined, and all of the books she has read on the forest and the magical residents of her world can't help.