This one was hard - it's definitely not the first house that comes to mind, but it makes sense to me overall.
Eve rejects the spotlight usually, rather than embracing it, and has never really cared for power, preferring to perfect her skills just for the thrill of it, not in a way a Slytherin would.
She is definitely an adventure-seeker and is brave, but she's not exactly noble, nor is she self-sacrificing enough. She's a hero with restraint and would feel stressed in Gryffindor, though it's clearly a close second.
Eve is definitely one to put in the hard work it takes to be a Hufflepuff, content working behind the scenes, but she needs more adventure and excitement in her life.
So, Eve's most likely a Ravenclaw. She doesn't come off to most people as dedicated to knowledge, but it's one of the things that attracted her to being a spy for so many years. She's passionately dedicated to her individuality and her creativity, which she expresses through her interactions with people, rather than art. Her defining characteristic is her wit.
The Scarf of Sexual Preference says: The Brain Is The Sexiest Organ