well with regard to Sir JOhn and Mrs Jennings being insensitive, that is the way that they are. In a pracitical sense tehy are usually good natured and willing to help people..(sir J giving the Dashwoods the cottage, Mrs J nursing Marrianne etc)but they woudl never understnand the "finer feelings" and sensitivities of people like Brandon, Elinor and of course ESPECIALLY someone so "emotionally precious" as Marianne. When Mrs J feels that with Willoughby having let M down, she is now free to fall for COl Brandon, she means well, but she simply can't understnad that someone like Marrianne or even Elinor would not be able to change their minds so quickly on losing one lover....