Jane's character in Chapter 36 is a mature, more independent, and determined woman than she was when she first arrived at Thornfield. She has finished her figurative journey of self-discovery at this point in the novel and embarks on a literal journey back to Thornfield to address the premonitions that she now attends to rather than squelching them.
To illustrate this major change in Jane's once timid character, Bronte relies mainly upon stream-of-consciousness writing. While the whole novel is told in first person, this chapter gives the reader more of a glimpse into Jane's thought process. The reader sees her inner conflict through several longer passages that are Jane's conversations with herself. For example, at the beginning of the chapter when St. John takes off, Jane thinks,
"My spirit . . . is willing to do what is right" (423)
and she continues to think about what choices lie ahead of her. Later when she views Thornfield again after several years, she lapses into another soliloquy (in her mind) about her feelings toward Rochester and the action she is about to take (426). This technique allows Bronte to make Jane's character more proactive than she has been before to the reader.
Well, of course we are approaching the end of the book here in chapter 36, and Jane has matured into a model young woman (some critics say that she was ALWAYS a mature and model young woman). I thought it might be helpful to be more specific about chapter 36 instead of general about Jane's maturity. Much of the chapter really has to do with Jane learning what has happened to Rochester. Jane leaves for a while (after St. John departs). Her reasoning is thus:
[I am traveling for four days] to see or hear news of a friend about whom I had for some time been uneasy.
Of course, it is Rochester that Jane is going to see. Unfortunately, when she arrives, she finds that Thornfield is burned to a crisp. Jane is absolutely in panic mode as she tries to ask the local business owners what has happened. In the midst of it all, she learns that Bertha set fire to the building and then killed herself by jumping from the top. Rochester lives, however, and is residing at Ferndean. Rochester has supposedly had his hand amputated due to an injury and has been bruised up, but he is okay. Jane rushes to his side, bringing water to him on a tray when she is not "allowed" to be admitted. The reunion is so very touching:
"In truth?—in the flesh? My living Jane? . . . My living darling!” [To which Jane is pleased to reply,] “I am an independent woman now.” ... “Am I hideous, Jane?” Jane replies, “Very sir; you always were, you know.”