This is a seriously interesting question to consider, and you will find that there are a whole range of responses to this question. My own personal feeling is that there are some issues that are not so easily resolved as the happy ending that is suggested in the novel would indicate.
Let us remember that this is a novel that is focused on the internal conflict within Jane Eyre herself and the way that she is shown to battle between cold, intellectual reason and fiery passion. We see these two extremes again and again through the novel, such as the incident in the red room when she is dominated by passion, and then when she decides to leave Thornfield when she is dominated by reason. In a sense the rest of the characters she meets are dominated by one of these two extremes.
However, by the end of the novel, with the events that have transpired, and in particular the maiming and blinding of Rochester, himself a character who is shown to be dominated by passion, that somehow Jane has reached a stage in her life where she is able to balance both of these extremes and live a happy and conventional life as a result. In particular it is strongly suggested that one of the reasons that their marriage is successful is the way that Rochester has been "taken down a peg or two" and reduced to a position where he is physically dependent upon Jane, making them equals. Note what the text tells us:
Mr. Rochester continued blind the first two years of our union: perhaps it was that circumstance that drew us so very near--that knit us so very close! for I was then his vision, as I am still his right hand.
However, I personally find myself doubting that the image of Victorian respectability that Jane manages to exude is something that can be easily balanced with the extremes that Jane demonstrates during the novel. I am not so sure that the powerful symbol of repressed female sexuality suggested in the character of Bertha Rochester can be killed off so easily, or hidden away metaphorically in the attic of Jane's mind. My complaint is that I find the ending too neat.