Algernon: My dear fellow, the way you flirt with Gwendolen is perfectly disgraceful. It is almost as bad as the way Gwendolen flirts with you. (I.35)
Because girls are under such strict moral codes in the Victorian era, it is dishonorable for them to be seen flirting publicly with men, especially single men. On the flip side, it is also socially questionable for a man to be seen flirting with a woman since that would be interpreted as leading her astray.
Algernon: Well, in the first place girls never marry the men they flirt with. Girls don't think it right. (I.47)
According to Algernon, "girls never marry the men they flirt with" because "girls don’t think it right." This shows that the types of men women marry are different from the type of men they flirt with. Flirtation usually means that two people are attracted to each other. If women don’t marry the men they flirt with, this means they marry men to whom they are not attracted.
Jack: […] you have no right whatsoever to read what is written inside. It is a very ungentlemanly thing to read a private cigarette case. (I.59)
Unlike Algernon, Jack has a sense of morality, which he defines as what is "gentlemanly." To Jack, it is dishonorable or "ungentlemanly" for a man to pry into another’s private life. He distinguishes between the public sphere and the private in a way that Algernon does not—as evidenced by Algernon’s later desire to peek into Cecily’s diary.
Lady Bracknell: What is your income?
Jack: Between seven and eight thousand a year.
Lady Bracknell: [Makes a note in her book] In land, or in investments?
Jack: In investments, chiefly.
Lady Bracknell: That is satisfactory. What between the duties expected of one during one's lifetime, and the duties exacted from one after one's death, land has ceased to be either a profit or a pleasure. It gives one position, and prevents one from keeping it up. That's all that can be said about land.
Jack: I have a country house with some land, of course, attached to it, about fifteen hundred acres, I believe; but I don't depend on that for my real income. In fact, as far as I can make out, the poachers are the only people who make anything out of it.
Lady Bracknell: A country house! How many bedrooms? Well, that point can be cleared up afterwards. You have a town house, I hope? A girl with a simple, unspoiled nature, like Gwendolen, could hardly be expected to reside in the country.
Jack: Well, I own a house in Belgrave Square, but it is let by the year to Lady Bloxham. Of course, I can get it back whenever I like, at six months' notice.
Lady Bracknell: Lady Bloxham? I don't know her.
Jack: Oh, she goes about very little. She is a lady considerably advanced in years.
Lady Bracknell: Ah, nowadays that is no guarantee of respectability of character. What number in Belgrave Square?
Lady Bracknell: [Shaking her head] The unfashionable side. I thought there was something. However, that could easily be altered.
Jack: Do you mean the fashion, or the side?
Lady Bracknell: [Sternly] Both, if necessary, I presume. (I. 184-198)
What the upper class considers respectable is wealth and style. This is shown in Lady Bracknell’s interest in Jack’s assets when considering whether or not he is a proper suitor for Gwendolen’s hand. It is also important that Jack has enough wealth to afford both a country and town house.
To pass Lady Bracknell’s test, Jack must live in a fashionable area in the city. Because of her pride in her rank, Lady Bracknell assumes that Jack will gladly either relocate his house to the fashionable side or change the current fashionable trends.
Lady Bracknell: [….] Mr. Worthing, I confess I feel somewhat bewildered by what you have just told me. To be born, or at any rate bred, in a hand bag, whether it had handles or not, seems to me to display a contempt for the ordinary decencies of family life that reminds one of the worst excesses of the French Revolution. And I presume you know what that unfortunate movement led to? As for the particular locality in which the hand bag was found, a cloak-room at a railway station might serve to conceal a social indiscretion—has probably, indeed, been used for that purpose before now—but it could hardly be regarded as an assured basis for a recognised position in good society. (I.200-214)
The most important criteria for respectability in Victorian England was one’s bloodlines, especially if they were aristocratic. Lady Bracknell asks whether Jack’s wealth comes from "the purple of commerce" or from "aristocracy" because the upper classes had more respect for aristocrats. That Jack has no idea who his family is, and was "found" at birth in such an unpromising place as in a handbag at a train station, immediately makes him a ridiculous prospect for marriage with Gwendolen.
Cecily: Dear Uncle Jack is so very serious! Sometimes he is so serious that I think he cannot be quite well.
Miss Prism: [Drawing herself up] Your guardian enjoys the best of health, and his gravity of demeanour is especially to be commended in one so comparatively young as he is. I know no one who has a higher sense of duty and responsibility. (II.4-5)
As an older character with a staunch sense of morality, Miss Prism admires Jack for his apparent "gravity of demeanor," especially since he is "so comparatively young"—twenty-nine years old. She admires his "sense of duty and responsibility" and espouses the same for Cecily. But young Cecily, who values pleasure and romantic love above all, sees Jack’s "respectability" as tiresome and even a sign of possible illness.
Lady Bracknell: And now that we have finally got rid of this Mr. Bunbury, may I ask, Mr. Worthing, who is that young person whose hand my nephew Algernon is now holding in what seems to me a peculiarly unnecessary manner? (III.56)
Like public flirtation, public hand-holding between two unmarried individuals is highly inappropriate in the Victorian era—as Lady Bracknell makes quite clear. But the fact that Algernon and Cecily continue holding hands even after Lady Bracknell’s icy comment shows that their love (or recklessness) transcends their sense of propriety.
Chasuble: Both these gentlemen have expressed a desire for immediate baptism.
Lady Bracknell: At their age? The idea is grotesque and irreligious! Algernon, I forbid you to be baptized. I will not hear of such excesses. (III.111-112)
As a noble, Lady Bracknell is conservative in her religious outlooks. Even when practices such as baptizing adults are not forbidden by the Church, Lady Bracknell doesn't approve. She believes that because of her high rank, she knows better than others—even clerics—what is respectable in religious practice.
Jack: [Embracing her] Yes... mother!
Miss Prism: [Recoiling in indignant astonishment] Mr. Worthing! I am unmarried!
Jack: Unmarried! I do not deny that is a serious blow. (III.148-150)
By Victorian standards, an unmarried mother is a most scandalous and dishonorable individual. It means that she lost her virginity before marriage. In a time when female chastity was highly valued—and indeed, used as a bargaining chip in arranging marriages—an unmarried pregnancy was not only a disgrace, but a ticket straight out of the upper social circles.