With dramatic irony as a discrepancy between what a character thinks and what the reader knows to be true, Amanda's words to Tom that he "lives in a dream world and manufactures illusions" are ironic because they could easily apply to her, who operates in a world of illusions, also.
A former Southern belle who has fallen upon difficult times, Amanda creates illusions herself. For instance, in Scene 1, Amanda acts as though the shabby apartment is like her Southern home. When Laura offers to bring in the blancmange, Amanda tells her that she ill imitate "the darky" while Laura plays the lady.
"Resume your seat, little sister--I want you fresh and pretty--for gentlemen callers"
When Laura explains that she has no callers, Amanda replies,
"Sometimes they come when they are least expected. Why, I remember one Sunday afternoon in Blue Mountains--your mother received--seventeen!--gentlemen callers!"
Then, later in Scene 7 after her elaborate preparations for Laura's "gentleman caller," Amanda has adorned Laura in a new dress, whose hem she adjusts as she kneels before Laura in a "devout and ritualistic" manner. Amanda herself dresses in a girlish frock that she resurrects from a trunk and immerses herself in the "legend of her youth" as she greets Jim O'Connor in this girlish dress and with her Southern charm that is accented by her vivacity and exaggerated and accented speech. And, while she is in the kitchen and Jim and Laura converse, Amanda's forced "gay laughter" is heard.
Clearly, Amanda operates in a world of illusions. First of all, because she loves them, she believes that her children can do nearly "everything." In Scene 4, she declares to Tom,
"Why, you--you're just full of natural endowments! Both of my children--they're unusual children! Don't you think I know it? I'm so--proud!
Yet, she sadly discovers that Laura has quit the Rubicam's Business College. However, she works at selling magazine subscriptions to make enough money to "properly feather the nest and plume the bird"; that is, to make the apartment appealing to a gentleman caller for Laura, thus creating another illusion.
Amanda resumes her illusions when Mr. O'Connor is about to arrive as she speaks of him as though he has already proposed to Laura, commenting that she does not want a drinker and his eighty-five dollars a month "is not much more than you can just get by on...." Then, when Tom warns her that Jim does not know about Laura's being "very different from other girls," Amanda insists that Laura's "difference is all to her advantage" and asks Tom why he says that she is "peculiar."
At the end of Scene 7, Amanda accuses Tom of living in dreams and manufacturing illusions, yet she herself has done this as, ever the Southern Belle, she has dreamt of Laura and Tom's successes in both business and love as provisions for her old age.