No need.

You mull it over through dinner and well into the next day: should you try for something more? Do you dare upset the delightful balance you've managed to strike?

By noon the next day you have your answer: No. No, you were quite content where you were. You lay and basked in the morning light spilling in through the window, light that should have vaporized you. You talk and flirt with the endearingly nervous guardsmen, who would have crushed you with disgust if they knew your true form. You giggle and ogle the noble ladies, shaping up to be the perfect daughter for Mother while you forget you even have another body nestled within this one.

You learn the script of the unknown books, elvish, and spend whole days translating in the dusty library. Mother is shocked and amazed with your change of heart... but quickly accepts you when you become a respectable lady of high standing. You bring in tutors from around the world to teach you everything from mathematics to sorcery and you excel in the act of learning. Every so often you feel a twinge from Eirene but you give it no heed, the meaning is clear: screw you.

One day, some time after your house arrest had been lifted, you're laid out on a garden bench idly watching the clouds drift by. You smile beatifically at mother as she settles herself next to you on the bench, hesitantly returning your expression. In recent weeks the two of you had grown quite close and you had the impression she was still getting used to it. The two of you talk amiably for a moment before you notice a young man waiting patiently at the entrance to the garden, casting nervous glances over at the two of you. He's obviously a noble, more handsome than most, his stance and expression make it clear as day. Your mother notices your gaze and she gives you an expectant look, tinged with excitement, "What do you think? You'd be a lovely pair."

You're confused for about ten seconds before it suddenly clicks. "Oh. Oh. You want him to be my fiancee." She nods excitedly. Um... well. You sure didn't see that one coming.