In the incipit of the novel, why is "them" in italics in the sentence "Between them it was more the intimacy of sisters." What does it mean?

In Chapter 1 of s , the
character of Miss Taylor, recently married and now Mrs. Weston, is introduced soon after Emma
herself. Jane Austen writes:

Sixteen years had Miss Taylor
been in Mr. Woodhouse's family, less as a governess than a friend, very fond of both daughters,
but particularly of Emma. Between them it was more the intimacy of
sisters.

The italicized word them
refers to Miss Taylor and Emma, contrasting their relationship with that of Miss Taylor and
Emmas elder sister, Isabella, and also, by implication, with the relationship of Emma and
Isabella. At the time the novel begins, Isabella has been married for seven years. Since Emma is
nearly twenty-one, this means that Miss Taylor has been her governess since she was around five
years old. She was always a kind and indulgent governess to both girls but, since Isabella left
home seven years ago, when Emma was fourteen, Miss Taylor has become much more than a governess.
She and Emma have enjoyed a relationship of equal footing and perfect unreserve throughout
Emmas teenage years. Miss Taylor was therefore closer to her at a crucial time of her life than
her actual sister.

This opening, emphasizing Emmas closeness to Miss Taylor,
makes it clear that Miss Taylors marriage and removal from Hartfield will leave Emma in a state
of boredom and solitude, which she will attempt to alleviate, setting the stage for her
friendship with Harriet and her ill-judged matchmaking schemes.