The Stolen One by Suzanne Crowley.
Published 2009.
The following summary is obtained from Goodreads.
“No one wanted you. But I did.”
Kat’s true identity is a secret, even from her. All she has ever known are Grace and Anna and their small village. Kat wants more than the hours spent embroidering finery for wealthy ladies and more than Christian, the gentle young farmer courting her.
But there are…