Explain the concept of humorous in she stoop to conquer ?

When the play was first produced, it was discussed as an example of the revival of laughing comedy over the sentimental comedy seen as dominant on the English stage...

Comedy of manners

The play can also be seen as a comedy of manners, where, set in a polite society, the comedy arises from the gap between the characters' attempts to preserve standards of polite behaviour, that contrasts to their true behaviour.

Romantic comedy

It also seen by some critics as a romantic comedy, which depicts how seriously young people take love, and how foolishly it makes them behave (similar to Shakespeare's A Midsummer Night's Dream); in She Stoops to Conquer, Kate’s stooping and Marlow’s nervousness are good examples of romantic comedy.

Alternatively, it can be seen as a satire, where characters are presented as either ludicrous or eccentric. Such a comedy might leave the impression that the characters are either too foolish or corrupt to ever reform, hence Mrs Hardcastle.

Farce or comedy of errors

The play is sometimes described as a farce and a comedy of errors, because it is based on multiple misunderstandings, hence Marlow and Hastings believing the Hardcastles' house is an inn.