She could have no doubt – putting every thing together – that Jane was resolved to receive no kindness from her. She was sorry, very sorry. Her heart was grieved for a state which seemed but the more pitiable from this sort of irritation of spirits, inconsistency of action, and inequality of powers; and it mortified her that she was given so little credit for proper feeling, or esteemed so little worthy as a friend: but she had the consolation of knowing that her intentions were good, and of being able to say to herself, that could Mr. Knightley have been privy to all her attempts of assisting Jane Fairfax, could he even have seen into her heart, he would not, on this occasion, have found any thing to reprove.
– Jane Austen
Emma, Chapter 45. Jane Fairfax makes it clear that she doesn’t want a friendship with Emma. When Emma reaches out a number of times, she is rebuffed. As a result Emma feels wounded and embarrassed. If Mr. Knightley knew all that Emma had done to help Jane, he would find nothing to reproach her with, she believes. Emma views Mr. Knightley as her moral guide. But as usual, Emma is operating under wrong assumptions. As far as she is concerned Frank Churchill has affections for her and no interest in Jane. She has no clue that Frank and Jane are an item and are secretly engaged. And Jane sees Emma as a threat because of the flirtatious behavior that has taken place between Emma and Frank.