This is a very detailed broad question as there are a number of women, each with different roles, in both Jane Eyre and Romeo and Juliet. I will speak to the two major women and describe briefly the chief points of their roles; this will give you a springboard for further examination that you can incorporate into your originally written essay.
In Romeo and Juliet, Juliet holds the principal woman's role. She is a pampered, cherished young woman of great charm and beauty who has never known hardship. She soon finds herself in the midst of a great moral conflict as she decides to defy her parents and reject their wishes; deceive them and the rest of the world through a secret marriage to her family's sworn enemy; learns that her cousin was slain by her husband's hand; agrees to the dangerous exploit of feigning her own death in order to live with her choices in love.
JULIET: O comfortable friar! where is my lord?
I do remember well where I should be,
And there I am. Where is my Romeo?
In Jane Eyre, Jane has the principal woman's role. She starts as a troubled, mistreated, unhappy and rejected girl of little beauty or charm but with a propensity for speaking forthrightly and valuing moral behavior. She finds her troubled path smoothed considerably over the years, preparing her for the trials and conflicts that come her way as her life's desires butt up against the desires (and the complicated lives) of the two principal men who wish to control her choices.
The woman's role Juliet most prominently demonstrates is that of the limited freedom of choice--some might describe it as "no choice"--that even beloved and well treated women suffer under. Juliet is as free as a butterfly until it comes time for her life to juxtapose with the questions of power, wealth, and social importance, which are questions that did--some might say must--govern betrothal for marriage.
The woman's role Jane most prominently demonstrates is that of the consequences to a woman of insisting upon and sacrificing for independence of thought, means, choice, and life circumstances. Jane experienced these consequences from an early age, for example, her horrid encounter with the red room, and they pursued through out her lifetime. This continued circumstances changed the ideas of those who would subjugate her. For instance, Jane was forced to flee from Rochester, then from Rivers, when each in turn had their own ideas for her life choices. Only when Rochester was stopped in his tracks from projecting plans for anyone else could she assert her own terms for her own life and join with her beloved Rochester in making a new life of mutual accord.
Diana announced that she would just give me time to get over the honeymoon, and then she would come and see me.
“She had better not wait till then, Jane,” said Mr. Rochester, when I read her letter to him; “if she does, she will be too late, for our honeymoon will shine our life long: its beams will only fade over your grave or mine.”