The conventional answer to this would be Jane Eyre, who is, after all, the protagonist of the novel and a sort of stand in for the author herself. I think that it might be more interesting though, to argue that it is only by several rather improbable plot manipulations that the author manages to pull off the Rochester-Jane Eyre romance. To make it convincing, the author ends up gifting Jane with a fortune, killing off Bertha, and mutilating Rochester, as well as several other improbabilities including telepathic communication.
In a more realistic novel, Blanche, a beautiful young woman of Rochester's own social and economic class, would be an obvious match for Rochester. It is true that Blanche's motives are primarily financial, but that was how marriage worked among the upper classes of the period. Blanche's background would have made her skilled in managing a large household of servants. The bigamy plot would work equally well with Blanche as the romantic interest. Moreover, Blanche and Rochester, both cynical and worldly, would have been a more appropriate match and probably had a better marriage than the older, worldly Rochester and the far younger, unsophisticated, and sternly moralistic Jane.