Charlotte’s assumption on invalids
When Mr. Parker's siblings invite Charlotte, they tell her that they suffer from invalids, which makes them not get around well. Ironically, Charlotte assumes that they are making up their ailments because she thinks they are in perfect health. The reader finds it sarcastic when Charlotte compares Mr. Parker's siblings to other people instead of understanding and accepting them as they are.
The irony of Lady Denham
Lady Denham knows that her nephew Edward is a hopeless person, but she wants to hook him with Miss Lumbe, a young rich heiress. It is satirical that the primary motivation for Lady Denham to organize a marriage between Edward and Miss Lambe is to get a share of the wealth Miss Lambe has. A feckless character like Edward does not deserve a hardworking and wealthy woman like Miss Lambe.
The irony of the portraits
In Lady Denham's house, Mr. Denham's portrait is strategically positioned in the fireplace where everyone can proudly see it. The portrait of Lady Denham's first husband is neglected and put in a corner in one of the rooms. The irony is that the property that Lady Denham lives in belongs to her first husband, but she does not want to give him credit.
Lady Denham’s decision to live with Clara
Lady Denham is a rich woman because she inherited her wealth from her husband. The reader realizes that Lady Denham cannot share her wealth with any family member to her late husband. Satirically, her decision to live with her niece from her husband's family is because she is not interested in her wealth like other family members.
Diana's news that excites Mr. Parker
When Diana gets home, she tells Mr. Parker that there will be visitors from a girl's school to Sanditon. Mr. Parker is excited because the arrival of visitors to the town signifies the thriving of business. Ironically, the anticipated visitors later happen to be the family from the West Indies with their vacation property. Therefore, Diana's good news turns out to be formless and unhelpful.
