"The Ruined Maid" makes the reader into an eavesdropper. The poem launches right into a dialogue between two young women meeting in the street, and that dialogue is pretty telling.
From the very start of the poem, the reader has a sense of what kind of person the first of these two speakers is. Her cheery, colloquial greeting—"'O 'Melia, my dear, this does everything crown!'"—lets the reader know a great deal about her. She's friendly, she's enthusiastic, she's jolly—and she's lower-class. A Victorian reader might even be able to guess that she's from the countryside from this very first line; a modern-day reader will catch up as soon as she cries, "'Who could have supposed I should meet you in Town?'" That important-sounding capital T on "Town" suggests that this cheery lady might be the type to look up in awe at all the tall buildings.
The Amelia she's just met, meanwhile, seems like a different character altogether. Even from these first few lines, the reader can gather that Amelia has changed a lot since the last time her friend saw her. Not only has she come to "Town," she's well-dressed and wealthy now—with the implication that she absolutely wasn't before.
She's got an easy explanation for this, though, and her reply characterizes her as clearly as her friend's cheerful chatter. She answers her friend's astonished questions almost with a yawn: "'O didn't you know I'd been ruined?' said she."
It's here that the poem's profound irony kicks into gear. Amelia describes being "ruined"—that is, becoming an unmarried mistress, a serious sin in the eyes of Victorian society—as casually as she might describe getting a new pair of shoes. Not only does she take this ruination lightly, it seems to be the source of a whole new life for her—and one that seems to be treating her pretty well.
Her voice is also very different from her friend's: none of that thick accent, and none of that enthusiastic exclaiming. She's adopted an upper-class voice as well as an upper-class presentation.
The poem's use of overheard dialogue here thus makes a lot of thematic sense: it's as if the reader has become a passerby in the street, turning an ear to all the hot gossip. The steady rhyme scheme—AABB, a set of rhyming couplets—adds to the light, bouncy atmosphere, cluing readers into the fact that the poem is satirical. The same can be said for the poem's meter, anapestic tetrameter with an iamb thrown in at the start of lines (an anapest goes da-da-DUM while an iamb da-DUM):
"O 'Melia, my dear, this does everything crown!
Who could have supposed I should meet you in Town?