Responses

She had a reputation of being the good child - loving, frogiving, caring, giving, and she uses it to her advantage. MC was exploiting it basically, hence why she could not say "No" completely, she had to maintain the facade. Mielle is very calculating even for a child now and in their past life.
I get it's for the sake of moving forward in the plot but it's not that hard for Mielle to go "Oh, that dress is special, how about this or this." But I guess this comic isn't the only guilty one in doing something like that.