> But she could never get acquainted with her: she did not know how it was, but there was such coldness and reserve; such apparent indifference whether she pleased or not.

Mr Knightley agrees to Jane's being reserved.

And;
>and it had been always imagined that they were to be so intimate -- because their ages were the same, every body had supposed they must be so fond of each other."

We know how Mr Knightley nagged her about it. Pushing her against her will.

Can one imagine the stuation and feelings under these circumstances.
I guess one can speak in favour of who one chooses when one looks at this passage.

I wish Jane Austen had written about Jane Fairfax's thoughts as well.
What did she think about her behaviour to Emma (apart from the conversation between them towards the end). What were her feelings? We don't know??
So one sided knowledge of things can lead to harsh judgement.

When I talked of the past not being clear, it was meant for their growing up days before they became women, because this passage deals with their later stage in life. It's also not clear what Jane's thoughts were - in her mind, where one feels free to think
about ones real feelings - as Emma often does.