I had posted at earlier times (for example the Sotherton outing) that I felt that the whole thing was like a big masquerade of which Fanny was somehow disconnected. Everyone seems to be playing their own "role" (for which the play acting might also be a metaphor) whereas Fanny seems not to be playing a role. She is just herself. And she seems to perceive the other characters much more for what they are than through the glasses of her own hidden agenda (as the others often do).

Maybe it has to do with the fact that, since she was brought to the Bertram family from the poor relatives, she is basically an outsider. She was treated differently from the others from the beginning, and with the background of the poor family from her childhood she probably has a very different set of experiences, enabling her to see things from a more objective standpoint than the others.

But then, this is Fanny's character. If it had been a girl with a different character, who had been taken from the poor family and placed with the Bertrams, the story might have taken a very different turn.

The only other character that manages to see things from a more objective standpoint, I feel, is Sir Thomas after his return from Antigua. Probably because of the time and the experiences he had during his absence he appears to have a moment of epiphany where he see things differently from before his trip. He is still not quite able to see his daughters and Fanny for example for what they really are, but I have the feeling he is really trying.