Cecilia expressed her strong opinion about a man's character, suggesting that anyone who would choose to contract mumps must be capable of any sort of folly. This comment reflects her overall disdain for his lordship's lack of romantic behavior, which she finds unappealing. Lady Ombersley, on the other hand, understands Cecilia's feelings and agrees with her assessment of the man.
This interaction highlights Cecilia's frustrations with the current state of romance and the expectations she has for a gentleman's conduct. Lady Ombersley recognizes and validates Cecilia's sentiments, indicating that the societal norms of the time heavily influence their perspectives on love and attraction.