"I can ask the seamstress to come here and show you her patterns?"

I would like that.

So Jane goes and gets the seamstress, who comes in with sketches and pattern pieces to show Cyllene.

Oh!  This is a fascinating look into how humans do a complicated thing.  Cyllene likes this style, and this one, and she likes colors in general but it seems like the things she likes about them aren't really describable just by saying which color a thing is?  It's beyond her vocabulary.  If there are samples she can point at the best ones, though.

The seamstress can run and get swatches!

Cyllene turns out to like kind of bright colors, sometimes pastels, and tertiaryish ones hue-wise.  She does not have a human sense of what colors 'go' together, let alone a contemporary one, and is happy to defer to a specialized human on what combinations are good.

The seamstress eventually comes to mutually agreeable conclusions and goes off to make her the dress she wants. It will take a while.

Great.  Her letter is done being drafted, but she did make a few handwriting mistakes here and there, and maybe she should rewrite a clean copy?  She rewrites a clean copy, very carefully.

Cymbeline swings by while she's still doing that.

She hands him the letter!!!  The one she's writing, and then the one with the scratched out bits!

Prince Cymbeline,

I am very grateful for your household's generosity in hosting me. I have found more joy in my time here more than my whole life in water before it, and hope to continue to bring more prosperity to your land for many years to come.

You have lingered in my mind since we met, perhaps obviously.  The way you interacted with me when I was a mere fish to you belied a kindred curiosity, and I continue to see that and a sharp intelligence in you.  It could have been the case that your interest in a lowly shark-person was only idle and and passing; I count myself fortunate that this was not so.  That, on top of this, you are also the prince of a marvellous country - I expect it provides an opportunity for us both which is rarely matched in quality.

At the present time, I cannot continue relations with almost anyone from my

(Here he has to switch and find his place in the previous copy.)

previous nation, nor can I access more than a small fraction of my previous power.  This will not remain the case forever.  I hold hope (tempered with reason) that in the future, I will command more magic than ever before, and bring luxury and stability to your people and mine.

Please consider marrying me.  The outcome I see benefits both our populaces, as well as each of us individually.  I humbly offer this gift as a symbol of my magical skill and personal dedication.

With hope,
Princess Cyllene

Wow that's quite a letter. He reads it twice. "I - confess the idea had crossed my mind - did I interrupt you with respect to the gift or was the second draft not going to have that line or -"

Tuning fork with a red ribbon around it!!!

...he twongs it against the desk.

It plays the first song she sang to him, though - oddly.  It doesn't sound like it's being played on a tuning fork, nor a similarly-constructed proper instrument like a glockenspiel.  It's - as if metal were doing an impression of strings, almost.  He can hear a plucking nature in the tone coming out of the long, single ringing.

The song lasts two or three minutes, growing in complexity as it continues.  (If he tries to magically discern the properties of his gift in that time, he'll discover that the fork is entirely mundane and the magic is all in the ribbon.)

"- that's so cunning, will it sound different if I tie the ribbon around something else?"

Nod!

"Would you be able to make a sound if it were tied around your wrist?" he wonders.

Soundless giggle.  She offers her arm.

Tie tie.

Eeeeeee.  - She claps her hands together, once.  (Again.)  It doesn't sound strange enough to be very suspicious to anyone who wasn't expecting it; there's maybe a note and a half if you're listening closely.

"Huh." He takes the ribbon back and puts it back on the tuning fork. "- I'd have to get my parents' permission. They're very reasonable people but they'll have - questions, about the political situation with the sea people in particular, and concerns about how you'll go over with the church and the nobility, and - but I do like the idea."

Nod nod nod.

"I can try to anticipate what they'll say... they're not going to love the thing where you don't get along with your father, or the prospect of being obliged to take sides in a civil war if your uncle makes a move and has a fight on his hands."