I had high hopes that Bianca knew all along that Bella would make such a move. And that maid was sent by her to Bella to create an act as if the book was really burnt. Then she'll do a big reveal that it was all a charade from her.
But I was wrong. In the end, she was saved because of the plot armor.
I don't understand the running gag about Shin not having common sense. He was literally an adult from his previous life so why is he lacking it and why does it need to be taught to him? Is this just bad writing or intentional or both?