As is the case in many plays, the irony in She Stoops to Conquer is mostly dramatic irony. Readers know more than the characters, which produces humor for readers. For example, Marlow’s rude behavior is funny because readers understand that he does not realize that he is at a private residence. The play also contains verbal and situational irony. Verbal irony arises when a character says one thing, but means the opposite; thus, verbal irony and sarcasm can often be used interchangeably. Situational irony is found when the expected outcome of a situation is subverted.
" I'm in love with the town, and that serves to raise me above some of our neighbouring rustics;..."See in text(Act The Second)
Here, Mrs. Hardcastle’s descriptions of London and its neighborhoods create situational irony for her. While she is attempting to convince Hastings of her sophistication and love of urban life, the same love that raises her above those around her, she is in fact proving that she does not know much about London. This subverts her expectations of the situation and creates situational irony that she herself is unaware of.
"Ranelagh, St. James's, or Tower Wharf..."See in text(Act The Second)
Hastings is giving Mrs. Hardcastle a back-handed compliment: Ranelagh Pleasure Gardens, in the Chelsea area of London, were frequented by the upper class and royalty, as was St. James's Park. The Tower Wharf, on the other hand, was associated with thieves, prostitutes, and vices in general.
"I beg you'll proceed..."See in text(Act The Second)
The joke here is that Miss Hardcastle is completing Marlow's thoughts for him and, at the same time, making him feel as if he is doing all the talking.