You need to be at least Level 55 to receive this quest. You need to be at least Level 49 to turn-in this quest. This quest becomes trivial above Level 65.
Spoiler Alert! We have some more information about how to perform this quest but recognize you might want to try it on your own before we tell you the secret...
After defeating Victoria you will still have 2 very angry Aren Guards. Whether you finish killing them or not, after a certain time following Victoria's re-death you will be punted out of her instance and to a garden in the village behind the castle to speak to Jessie Mocliff.