Oh dear finally, in the anime and manga there is a misunderstanding that Sophia is in love with Katarina but she is not. She loves Katarina (in a friendly way) and his brother too much that she wants them to end together. I know is not the main point but I am happy that she actually read the novel because the anime's production and other authors seems that they haven't.
Sorry for my English when I get hyped I made a lot of careless mistakes.