together with the main theme throughout the play to demonstrate to his audience how deceptions and class distinctions can impact love, courtship, and marriage.

The overriding problem leading to the tension in this play is the social stratification in England. For example, protagonist Marlow generally treats people badly whenever he perceives that they are members of a lower social class. He tends to be pompous and disrespectful. Kate is a woman of the upper-class in society. However, her old-fashioned father forces her to dress more plainly than she would prefer. However, Hardcastle, Kate’s father, has chosen Marlow to be Kate’s husband. She is reluctant because of his reputation for being reserved and fears a boring marriage.

When Marlow mistakes Kate for a barmaid, she decides to pretend to be a woman of lower social class in order to learn more about him. She “stoops to conquer” him. Marlow is ultra-shy around women of his social class, but tends to open up in the presence of those he perceives to be of a lower social status.

Goldsmith’s theme is clearly evident throughout the play. He demonstrates that reality is often distorted by social status. The snobby British social system actually encourages hypocrisy. The protagonist is awkward around upper-class women. He becomes himself around those he deems beneath him. Goldsmith’s theme works both ways. In order to express her true feelings for Marlow, Kate must maintain her barmaid image. The author’s minor themes of love, deception, and class divisions are interwoven between the main themes of false appearance and reality among the stuffy English customs of the eighteenth century.

If there's one thing we can learn from She Stoops to Conquer, it's that a rigid social system effectively encourages people not to be true to themselves and each other. Everyone in the social order, especially those in the upper echelons, are expected to act out a part they've been given as if they were actors in a play. Due social propriety must be maintained at all times, lest the delicate fabric of society be irreparably damaged.

As the various characters in the play discover, however, this creates problems, not the least of which is the distortion of reality which it generates. Above all, the characters in the play find that acting out a social role—deliberately distorting the reality of their personalities—means that they cannot be themselves.

One only has to look at Marlow to see an illustration of this. Keeping up the facade of a country gentleman means that he cannot let his hair down in the presence of women of his own class. That's why he finds it so much more congenial to socialize with women from further down the social scale.

By the same token, Kate has to pretend to be a humble barmaid in order to show her true feelings for Marlow. Her cunning disguise is a very physical manifestation of just what elaborate lengths people have to go to in this rigidly stratified society in order to be themselves.

The predominant theme of this play is appearance versus reality, but since this is common in literature, the question becomes how it is expressed in She Stoops to Conquer. What Goldsmith explores in the play is how social roles impede us from being ourselves and how damaging this can be. For example, Marlow, the character that Kate "stoops to conquer," becomes a different person depending on what social class he interacts with. Around people who are his equals, he is embarrassingly shy, inept, and seemingly foolish. However, around lower class people, such as innkeepers and barmaids, he is bold and confident. This is played for laughs: we all know someone, in some contexts confident, who is reduced to a mass of inarticulate stammering when thrust into a different role. As Marlow says:

The folly of most people is rather an object of mirth than uneasiness.

Kate, an upper-class woman who is forced to dress plainly by her old-fashioned, sensible father, is mistaken by Marlow for a barmaid, and so he treats her with confidence. She sees a side of him other upper-class woman don't see. She determines to keep up the appearance of a lower-class woman until she has won his affections and then reveal her true identity. This will upset Marlow, though all will turn out right in the end.

The point is that both Kate and Marlow are who they are at core regardless of the public roles they play. Goldsmith invites us to think beyond facades to who a person truly is. We lose out when we don't embrace our best selves, as Marlow expresses to Kate when he describes his shy upper class persona:

I have lived, indeed, in the world, madam; but I have kept little company. I have been but an observer upon life, madam, while others were enjoying it.

She Stoops to Conquer has a variety of themes. Appearance versus Reality permeates the play, because main character Marlow can only feel comfortable in his own skin when he is the company of people who are not his peers.

Since Marlow cannot accept his reality, and he needs "the look" of something to find his comfort zone, it is safe to argue that he is guided by the appearance of lower class folk rather than by the real personality of people.

This theme is also evident in the way that Kate had to transform herself in order to get to Marlow. When she "stoops" and poses as a bar maid to get to know Marlow's real personality the roles become reversed and it is she who is basically fooling him.

Similarly, other characters seem to break with the expected social conventions that make men and women behave in a very specific way during courtship. This means that they adopt a personality in public and another personality in person. For example, Kate acts quite proper as her father tells her, but once this ends she is committing the unthinkable by actively pursuing Marlow. Again, this is indicative of the false versus real personalities that the characters adopt.

Other sub-themes include courtship, social conventions, gender roles, and family relationships, but notice how the theme of appearance and reality still affects these subtopics because the basic problem of the play, which is to bring Marlow and Kate together, can only occur when one of them adopts a fake persona.

The main theme of Oliver Goldsmith's She Stoops to Conquer is identity, particularly misrepresented and mistaken identity. Let's look at some examples.

At the beginning of the play, Marlow and Hastings get lost and Tony Lumpkin decides to play a little prank on them and on his stepfather, Mr. Hardcastle, by misrepresenting the Hardcastle home as an inn. The two young men fall for it, and when they arrive at the "inn," they show a side of their identity that is hardly flattering. They snobbishly treat the wealthy, important Mr. Hardcastle like an innkeeper. Needless to say, this does not make him especially pleased.

Constance tells Hastings the reality of things, but they agree to continue to deceive Marlow for fear that he will leave in embarrassment. Marlow is a suitor to Mr. Hardcastle's daughter, Kate, who likes him well enough except for his extreme nervousness around her. Apparently, Marlow never gets a good look at Kate's face, for later he mistakes her as a barmaid.

Kate decides to play that role to see if she can get a look at another side of Marlow's personality, and she certainly does. He flirts and compliments her and even tries to kiss her. Kate's father walks in on that show and is, again, not at all pleased.

Meanwhile, Tony and Constance pretend to flirt with each other to keep Mrs. Hardcastle in the dark about Constance and Hastings's plans to elope. Mrs. Hardcastle falls for the misrepresentation because she has already decided that she wants Tony and Constance to marry, even though they aren't at all interested in each other.

In the end, everything works out. The right couples get together, and everyone's identity is revealed. But the characters have taken a twisted path of deception in the process.

One crucial theme of the play, besides those mentioned in the other answer, is how social class affects the relationship between men and women. Marlow is only comfortable around women of lower social classes; he knows how to talk to them because he doesn't think he's required to treat them with respect. Around upper-class women, by contrast, he's profoundly awkward, as he seems to have no idea how to speak respectfully to a woman. Marlow's class bias and sexism combine to create a profound disjunction between the way he treats the two different categories of women. Kate uses her knowledge of this aspect of Marlow's character to manipulate him and get to know him without his realizing that it is she he's talking to, which would have rendered him unable to communicate. Through the experience of being deceived and then learning his mistake, Marlow grows as a person, such that Kate is willing to marry him in the end.