Assassins Oath (Sebastian x Reader)

Young assassin (F/N) (L/N) works for the group The Black Shadows which is a place where assassins go to get jobs from the rich. One day (F/N) is assigned to kill the Phantomhive butler and she accepts when she hears the reward is a very large amount of money. They say that he has extraordinary skills and that he must be eliminated immediately so (F/N) dresses up as a homeless woman to trick the lord Ciel Phantomhive into letting her stay for one week and of course it works. (F/N) almost immediately meets Sebastian who is also her target and hangs around him a lot but soon she feels her feelings for him change. What will (F/N) do when she develops an attachment to her target?