Manners

In a way I appreciate the manners/sense of decorum with which Jane Austen imbues some of her characters. Some people these days could learn from them. However, manners can be taken too far. In the book "Mansfield Park," Fanny was approached by a man (Henry) who wanted to marry her. She did not feel that he was an upright person, and had proof of it that involved one of her cousins. When she was telling her uncle (with whose family she lived) that she would not marry Henry, she was unwilling to support her view by telling him about the inappropriate behavior of her cousin and Henry. This left the uncle thinking that Fanny really didn't have any non-selfish reason for not marrying Henry, and he became quite angry. Even if Fanny should not have spread the word to others about Henry's improper behavior, it seems it would have been right for her to have shared it with her uncle under the circumstances (and maybe even outside those circumstances). Or would you call that slanderous speech or speaking evil of another?