She's cold, snarky, and easily annoyed with Mirai's antics.
I'm not expecting to find someone precisely like in the video, but they give a good example of her attitude and overall voice.
Surprise me! Maybe you come up with something better i never thought of.

And honestly I'd love for her to have some sort of European accent, or any accent really, so if you have an accent, please write where it's from!
It's not necessary, but i definitely favor a different accent than anything American, considering this show takes place in Europe Scandinavia.
Here's a list of a few i could imagine

French, spanish, anything from africa, german, anything Scandinavian, russian, etc.