[Even though Marie has given a Modranicht gift to Mettaton before, they have not actually met in person yet. She has not seen his robot form and she definitely was not aware that there was someone among the Mirrorbound who was basically a big, metallic and rectangular box.

(If it was something she could have guessed, he would probably have got something different for Modranicht than cookies, something more suitable for robots)

But she did not, so her reaction to Mettaton is as one would have expected of her]

I absolutely agree! I grew to love Aefenglom but what I would not do to have theatre and performances more acceptable in our city... We have so many talented artists and entertainers, it is such a waste that their skills have been forced into hiding! Such a shame...

[She greets him with enthusiasm, of course!]