After arriving home, Elizabeth can't wait to tell Jane that Mr. Darcy proposed, and when they are finally alone, she delivers the news. Jane is at first astonished, but this feeling quickly passes as a "strong sisterly partiality . . . made any admiration of Elizabeth appear perfectly natural." In other words, Jane thinks so well of her sister that it seems reasonable to her that a wealthy and haughty lord would propose to Elizabeth, even if she lacks a dowry.

Jane's feelings then quickly slide into concern for Mr. Darcy's emotions. Jane wonders about and "grieves" for Mr. Darcy's disappointment and unhappiness, noting that his disappointment must be all the worse for having been so sure Elizabeth would say yes. Elizabeth dismisses this, being sure Darcy will soon be over her and quickly move on to other interests.

Elizabeth then asks Jane if Jane blames her for refusing such a good match, and Jane says no, of course she doesn't—showing that she, like Elizabeth, values the idea of marrying for love, not money or status.

What is Jane's reaction when Elizabeth tells her about her proposal from Darcy in Pride and Prejudice?

Elizabeth's impatience to acquaint Jane with what had happened could no longer be overcome; and at length ... preparing her to be surprised, she related to her the next morning the chief of the scene between Mr. Darcy and herself.

Elizabeth was at once eager and reluctant to tell Jane about Darcy's proposal while she was in Kent and visiting at Rosings. She is eager because the whole incident is weighing on her mind. She is reluctant because her behavior was not above reproach as Darcy's letter to her afterward shows and as her own change of heart about herself proves.

"I, who have prided myself on my discernment! -- I, who have valued myself on my abilities! ... Till this moment, I never knew myself."

Elizabeth prepares Jane to be surprised before telling her but no amount of preparation could entirely squash Jane's surprise after all Elizabeth had said and felt earlier. Jane's emotional reactions are many. Our narrator says Jane is astonished but that it is tempered by Jane's knowledge of Elizabeth's worth which gives her "sisterly partiality" toward Elizabeth. For Darcy, Jane feels sorry for what he must have felt upon receiving a rejection (as does Elizabeth) when he thought that the marriage would be objectionable to himself only, though Jane also feels reproving of him for the wrongfulness of his manner of proposing. Jane feels no blame toward Elizabeth for refusing Darcy. When she hears about Darcy's letter, she is appalled at Wickham's "wickedness" and disconcerted about the situation between he and Darcy.

   "Indeed," replied Elizabeth, "I am heartily sorry for him; but he has other feelings which will probably soon drive away his regard for me. You do not blame me, however, for refusing him?"
   "Blame you! Oh, no." [Jane said.]

As a whole, Jane reacts to Elizabeth's news with many of the known emotions: surprise, disconcertedness, sorrow, astonishment and the others. Jane's reaction was therefore very complex and complicated.