It won't work

Jane, do you really think Mr. Rochester cares about you in the same manner you care for him? He knows you have feelings for him, and you know he has feelings for you, but he doesn't respect you. He is your boss, that's true, but if he wanted to be with you in a romantic way, then he would show more respect for you. A big way he does not show respect for you is that he is getting married. A conversation you two had stuck out to me.
He said “...the night before I am married! I am sure I shall not be able to sleep. Will you promise to sit up with me to bear me company? To you I can talk of my lovely one: for now you have seen her and know her.”
To which you replied with only a “Yes, sir.”
He then said, “She's a rare one, is she not, Jane?”
Again, you only said, “Yes, sir.”
If Mr. Rochester truly has feelings for you, then he would have sensed some discomfort that you had while talking about his future wife. This was not the case and he continued saying, “A strapper-a real strapper, Jane: big, brown, and buxom; with hair just such as the ladies of Carthage must have had. Bless me! There's Dent and Lynn in the stables! Go in by the shrubbery, through that wicket” (223)
Jane, do you see my point? Mr. Rochester is engrossed with Blanche Ingram; he begins to talk about her and of the things he likes about her, then he just leaves you where you are. From this conversation it would seem like you are the last thing on his mind.
When he gets married, what are you to do? It will be too late to express your feelings for him, lest you want to be a mistress. If you tell him now, do you really think he will leave Miss Ingram for you? She is a socialite and pretty, while you are the governess for Mr. Rochester's ward and not very easy on the eyes.
All that aside, does Mr. Rochester seem very fit for you? You are smart and level-headed; you should be able to remember all the flaws Mr. Rochester has, but love has blinded you too much. Mr. Rochester is disrespectful and arrogant.

Céline's Infidelity

“On recognizing him, the fang of the snake, jealousy, was instantly broken; because at the same moment my love for Céline sank under an extinguisher. A woman who could betray me for such a rival was not worth contending for: she deserved only scorn; less, however, than I, who had been her dupe.” (146)

Here Mr. Rochester speaks about Céline being disloyal to him. He is telling Jane of the account where Céline cheated on him with another man. On one or two occasions, I too have felt this jealousy rush through my body like the venom of a snake bite. This quote reminded me of the time where my girlfriend left me for another guy. The jealousy rushes through your body so quickly at a sudden rush as if you are having a heart attack. Giving her everything she could ask for, only to throw it away for someone else is heart breaking. And the change of emotions for the girl is unbelievable. Just as Mr. Rochester described it; it is crazy how one minute you could love her and with one disloyal act, all that was there is gone. For Céline to trick him and do this behind his back was miserable, when she was aware of the love that Mr. Rochester had for her.