In Chapter 46 Elizabeth receives 2 letters from Jane. The second letter gives the information that Lydia & Wickham may not be married. Jane's letter also reveals more about (some of) the Bennet sisters and their relationships with each other.

" ... as to my father, I never in my life saw him so affected. Poor Kitty has anger for having concealed their attachment; but as it was a matter of confidence, one cannot wonder. I am truly glad, dearest Lizzy, that you have been spared something of these distressing scenes; but now, as the first shock is over, shall I own that I long for your return? I am not so selfish, however, as to press for it, if inconvenient. Adieu! I take up my pen again to do what I have just told you I would not; but circumstances are such that I cannot help earnestly begging you all to come here as soon as possible. I know my dear uncle and aunt so well, that I am not afraid of requesting it, ... ."

Kitty concealed Lydia's attachment to Wickham (and Lydia must have also written that she thought Wickham was in love with her?). So the 2 youngest sisters were still writing and sharing confidences. Jane is very upset, but she still thinks of Elizabeth -- not wishing to alarm her, pleased that Elizabeth has been spared some of the horror, and not wishing to ruin her holiday -- even though she does ask for Elizabeth and the Gardiners to return home.