How we cite our quotes:
I saw he was going to marry her, for family, perhaps political reasons; because her rank and connexions suited him; I felt he had not given her his love, and that her qualifications were ill adapted to win from him that treasure. This was the point – this was where the nerve was touched and teazed – this was where the fever was sustained and fed: she could not charm him. (2.3.27, italics original)
Jane is really hot and bothered by the idea that Rochester is going to marry Blanche, not just because she’s jealous, but also because she can tell that they are so unsuited and that Rochester himself knows exactly how flawed and unpleasant Blanche is. Jane herself knows exactly how to "charm" Rochester, how to argue with him and keep him amused and even how make him love her. Basically, the way Jane feels here is the way we feel when we see someone doing something badly that we know how to do well. She wants to take Rochester away and show Blanche how this relationship should be done – but she can’t. She has to watch and suffer in silence, as usual.
I have not yet said anything condemnatory of Mr. Rochester’s project of marrying for interest and connexions. […] All their class held these principles: I supposed, then, they had reasons for holding them such as I could not fathom. It seemed to me that, were I a gentleman like him, I would take to my bosom only such a wife as I could love; but the very obviousness of the advantages to the husband’s own happiness, offered by this plan, convinced me that there must be arguments against its general adoption of which I was quite ignorant: otherwise I felt sure all the world would act as I wished to act. (2.3.31)
Jane doesn’t get why anyone would not marry for love, especially if they’re rich enough to do pretty much whatever they want, but she figures there must be some reason that so many people who are already wealthy and important insist on marrying to get more money and status instead of to make themselves happy. Notice that Jane doesn’t talk about her own ideas about marriage – only the ideas that she would have if she were in Rochester’s place. Somehow Jane can’t conceive of herself needing to make a choice about marrying for love or status – only of a man like Rochester doing so.
"What tale do you like best to hear?"
"Oh, I have not much choice! They generally run on the same theme – courtship; and promise to end in the same catastrophe – marriage."
"And do you like that monotonous theme?"
"Positively, I don’t care about it: it is nothing to me." (2.4.49-52)
You remember what’s going on here, right? Rochester, disguised as the old gypsy woman, is trying to get Jane to admit that she’s in love with him. (Go back and read the summary of Book II, Chapter Four if you have no idea what we’re talking about.) The real question here is, do we believe Jane’s claim that marriage is "nothing" to her and that she doesn’t care about it? We already know that she’s in love with Rochester, but we also know that she thinks that relationship isn’t going anywhere.