Algernon: I really don't see anything romantic in proposing. It is very romantic to be in love. But there is nothing romantic about a definite proposal. Why, one may be accepted. One usually is, I believe. Then the excitement is all over. The very essence of romance is uncertainty. (I.39)
To Algernon, a key ingredient in love is uncertainty. This is why he considers a marriage proposal business instead of pleasure.
Gwendolen: … my ideal has always been to love some one of the name of Ernest. There is something in that name that inspires absolute confidence. The moment Algernon first mentioned to me that he had a friend called Ernest, I knew I was destined to love you. (I.141)
Gwendolen’s love is conditional, based on something silly like what her lover’s name is. She makes it clear that if his name were not Ernest, she could never love Jack. This shows that she might be mixing up real love, which is often messy, with the idealistic romances of books.
Gwendolen: Ernest, we may never be married. From the expression on mamma's face I fear we never shall. [...] But although she may prevent us from becoming man and wife, and I may marry some one else, and marry often, nothing that she can possibly do can alter my eternal devotion to you. (I.270)
Here, Gwendolen declares her eternal love of and devotion to Ernest. Usually, it is a male character who swears his love to a girl, but in a moment of gender role reversal, Gwendolen takes on task.
Algernon: I hope, Cecily, I shall not offend you if I state quite frankly and openly that you seem to me to be in every way the visible personification of absolute perfection. (II.195)
Algernon bases his declaration of love for Cecily on her looks. This reiterates the idea that a man’s love for a woman can be based initially on her physical beauty.
Algernon: Well, my own dear, sweet, loving little darling, I really can't see why you should object to the name of Algernon. It is not at all a bad name. In fact, it is rather an aristocratic name. Half of the chaps who get into the Bankruptcy Court are called Algernon. But seriously, Cecily... [Moving to her] ... if my name was Algy, couldn't you love me?
Cecily: [Rising] I might respect you, Ernest, I might admire your character, but I fear that I should not be able to give you my undivided attention. (II.238-239)
Cecily, like Gwendolen, bases her love on something silly. Because of this, readers also question Cecily’s love for Algernon, as they do Gwendolen’s love for Jack. We wonder whether or not their love is really just adolescent infatuation.
Jack: I wanted to be engaged to Gwendolen, that is all. I love her.
Algernon: Well, I simply wanted to be engaged to Cecily. I adore her. (II.367-368)
Both Jack and Algernon confess that they practiced their deceit and briefly betrayed each others' trust simply to meet and spend time with the women they love.
Cecily: Mr. Moncrieff, kindly answer me the following question. Why did you pretend to be my guardian's brother?
Algernon: In order that I might have an opportunity of meeting you.
Cecily: [To Gwendolen] That certainly seems a satisfactory explanation, does it not? (III.14-16)
To modern eyes, Algernon’s professed love is insincere because he could not possibly have loved Cecily before he met her. But his answer to Cecily’s question is simple, elegant, and appeals to her romantic nature, so it is accepted as a definitive declaration of true love.
Gwendolen: Mr. Worthing, what explanation can you offer to me for pretending to have a brother? Was it in order that you might have an opportunity of coming up to town to see me as often as possible?
Jack: Can you doubt it, Miss Fairfax? (III.19-20)
Jack’s professed love for Gwendolen is a little more believable. He had actually met Gwendolen before making up his younger brother, Ernest. Where he conjured up a fictional Ernest to see her as often as possible, she deliberately disobeyed her mother and traveled all the way out into the country to see him.
Jack: But my dear Lady Bracknell, the matter is entirely in your own hands. The moment you consent to my marriage with Gwendolen, I will most gladly allow your nephew to form an alliance with my ward.
Lady Bracknell: [Rising and drawing herself up] You must be quite aware that what you propose is out of the question.
Jack: Then a passionate celibacy is all that any of us can look forward to. (III.105-107)
The fact that Lady Bracknell promptly passes up such a worthy candidate as Cecily—rich, beautiful, educated, and charming—as a wife for Algernon, simply because she doesn’t want her daughter to marry Jack, shows that Lady Bracknell scoffs at love as a legitimate reason for marriage.