When Catherine is about 10, Dr. Sloper invites his sister, Lavinia Penniman, who has been left a childless widow, to stay with him temporarily. She ends up staying permanently, on the assertion that it’s good for young Catherine to have “a brilliant woman” near her—though Dr. Sloper has never been “dazzled” by the intellect, or even the reason, of any woman except for the late Mrs. Sloper. Aunt Penniman is very romantic, with “a passion for little secrets and mysteries.” Dr. Sloper suspects that when Catherine is about 17, Aunt Penniman will try to persuade her that “some young man with a moustache is in love with her.”
With the exception of his late wife, Dr. Sloper doesn’t have a high opinion of women in general—something that will have a lasting impact on Catherine’s upbringing and prospects. Aunt Penniman’s romantic nature and love of mysteries will also have an outsized influence on Catherine and in the story as a whole.
Catherine herself is healthy and plain, but not beautiful. She is good, obedient, modest, and truthful. She is not exceptionally clever and doesn’t shine socially. She idolizes Dr. Sloper, both adoring and fearing him and desiring nothing more than to please him, which she’s never entirely succeeded in doing. Dr. Sloper never lets Catherine know how much of a disappointment she is to him.
Catherine is a thoroughly average and pleasant girl in many respects, and a devoted daughter, but this isn’t enough for Dr. Sloper, who wishes she were exceptional and a standout within society, like his wife had been. Meanwhile, Catherine puts her father on a lofty pedestal.
By the time Catherine is 18, Dr. Sloper has largely reconciled himself to his disappointment in his daughter and imagines that she will never surprise him at this point. What most people misunderstand about Catherine is that she is deeply, “painfully shy”—not “irresponsive” or “insensibl[e].” In fact, “she was the softest creature in the world.”
Dr. Sloper’s assumptions about Catherine’s character establish some of the tensions to come in the novel—she will indeed surprise him, and in ways not to his liking. People tend to interpret Catherine as lacking in sensitivity because she is so reserved, but she’s actually extremely soft-hearted.