I understand why Manicia think like that, and it's really sad.
She feel like a burden and want to die, but she don't know she is the most important girl in the world for Rude.
could have been a pitiful and sarcastic way of saying it. hard to grab emotions espescially when faces aren't fully drawn but i could have seen it fit the context as well. but the change isn't wrong either.
She doesnt realize that he would not have became a knight or someone with all the achievements during their school life , if he didnt have her in his life. It makes me sad that she didnt think of that. Cant wait to read the next part >_<