Mrs. Hardcastle is the wife of Mr. Hardcastle and mother of Kate and Tony - the latter by a previous marriage. She is a woman overwhelmed by pride, and love fashion.
She is over protective of Tony, whom she cares about but fails to tell his true age for a reason personal to her. It is her poor upbringing of Tony that contributes to his sense of mischief. Mr. Hardcastle refers to them both as "a pair that only spoil each other".
Mrs. Hardcastle stands in constrast with her husband (Mr. Hardcastle). She often disagrees with her husband over issues. For instance, they cannot agree on the virtues and vices of city life. She complains that Mr. Hardcastle does not take the family to the city now and then "to rub off the rust a little'. They also differ in their attitude towards Tony's behaviour.
Mrs. Hardcastle is corrupt and selfish. Her plan to match Tony and Miss Constance Neville is motivated by a selfish km. 0 desire to keep Constance's jewels in the family. To ensure that she achieves her goal, she does everything possible to frustrate Hastings and Constance's relationship. When she gets the hint of the elopement plan, she quickly arranges to take Miss Neville off to Aunt Pedigree, some forty miles away.
Mrs. Hardcastle appears simple-minded in the way she falls victims to Tony's tricks quite often. Tony, for instance rides her round and round the house and she ends up in horse-pond. She foolishly believes that she is forty miles m home when she is just forty yards away from her door. She also mistakes her husband for a highway man on this same occasion. She symbolizes greed and materialism and ends up as the only character who remains unhappy at the end of the play.

Points to note:
(a) Mrs. Hardcastle as wife and mother of Kate Hardcastle and Tony Lumpkin - the latter by a previous marriage.
(b) Her relationship with Tony whom she dotes on and allows to go wayward.
(c) Her love of foppery and her determination to live like Mrs. Grigsby and others.
(d) Her incessant quarrels with Mr. Hardcastle who would rather tell tales about his past military exploits than pay attention to her nagging about city life and material wealth.
(e) Her greed which drives her to keep Constance's jewels for Tony whom she would have Constance married to.
(f) Her being easily fooled and made a laughing stock of by Tony as she falls to his pranks.