A Court of Thorns and Roses by Sarah J. Maas #1

Feyre is a huntress, but when she kills what she thinks is a wolf in the woods, a terrifying creature arrives to demand retribution. Dragged to a treacherous magical land she knows about only from legends, Feyre discovers that her captor, Tamlin, is not truly a beast, but one of the lethal, immortal Fae.
And there's more to the Fae than the legends suggest.
As Feyre adapts to her new home, her feelings for Tamlin begin to change. Icy hostility turns to fiery passion that burns through every lie she's been told about the beautiful, dangerous world of the Fae. But shadows are creeping in, and Tamlin has a dark secret that he cannot share. Fate brought Feyre to Tamlin for a reason, but saving him from the darkness that threatens his world will lead her down a path that she can never return from.