#39 Kushiel's Mercy by Jacqueline Carey

This is the last book in the second trilogy set in the world of Terre D'Ange. Imriel and Sidonie have told everyone they are in love and want to marry even though Imriel's mother is a traitor. The queen decides that if Imriel can finally bring his mother to justice then they can marry and she will not disinherit her daughter.  But before he can do this a powerful general comes courting the country and Sidonie,  His wizards put on a magic spectacle and the next thing that happens is Imriel is plunged into madness and the rest of the citizens of the capital think Imriel never loved her and she has now left with the general and becomes his bride. So Imriel must leave, find his love and break the spell both on her and the country. Carey wraps up the series nicely and you are not left hanging at the end of the book. TRue love lost and found again is an age old plot but it works very well here.