Emma is not only wrong about others, she also doesn’t know her own feelings. In fact she is in love without knowing it. When Harriet Smith after several Emma-induced disappointments, lets her eye fall on Mr Knightley, Emma is suddenly aware that Mr Knightley must marry no one but herself! This is one of the most beautiful recognitions of love in literature. Of course, after that Emma stumbles on to happiness. Harriet Smith returns to her first love – a gentleman farmer initially disapproved by Emma for her because his station in life was too low.
That puts the finger on one sore spot in Jane Austen: servants and other persons of a status lower than the small gentry to which she herself belonged, are about as important as the furniture and get the same treatment. They are never introduced as speaking characters in her novels. England was a harsh class society.
That is also true for Jane Austen herself, and women in a similar position. The lower gentry did not own land and the only occupations open to them were the clergy, medicine and the army. But these were closed to women. A woman like Jane Austen could only hope to make an advantageous marriage in order to secure her status and way of life. Otherwise she would be dependent on other family members (as Jane Austen indeed was). This explains the importance of courtship and marriage in Jane Austen's novels.
Emma on Gutenberg. Librivox recording of the novel. I read Emma in the Penguin edition.