If Gill Hornsby's research is to be believed, and the sisters were as inextricably linked as they appear to have been, clearly Cassie, herself, would have been lost had she married, for It appears that she existed almost to care for others. At times in the novel she overhears what others say about her, and while she may not like it, she does not alter her ways. She goes, time and again, to help her brother and his wife with their family, and looks after her own mother and sister as well. She realized that marriage to Tom - had it occurred - would have resulted in a far different reality than she realized as a young woman in love. It would have, for example, separated her from Jane, who would never have written the novels that eventually made a name for her, provided an income for her, the novels that allowed for her earliest works to become well known as well. It allowed Cassie to be present in the home when her father died, to continue to help Jane have the freedom to write by relieving her of household duties that she, Jane, worried would rob her of her precious writing hours, and ultimately, it led Cassie to look after the reputation of the family's and most pointedly, Jane, as is the novel's focus. Clearly, as scottishrose says above, Jane may never have become the household name she now is - and Hornsby would never have felt the interest or need to write this book.