Austen's technique for imputing two meanings to her narratorial statements through verbal irony--remember that in the text, it is the narrator we hear, not Jane Austen (although one of the charms of Austen's works is that we believe the narrator's voice is identical to Jane's)--is complex and involves syntax, grammar and subject matter. In order to answer your question, an analysis of these three elements in ironic statements is in order. As always, Austen introduces the story of Emma with a brilliantly ironic statement from the narrator:
The real evils, indeed, of Emma's situation were the power of having rather too much her own way, and a disposition to think a little too well of herself; these were the disadvantages which threatened alloy to her many enjoyments. The danger, however, was at present so unperceived, that they did not by any means rank as misfortunes with her.
Let's analyze this to see how Austen uses verbal irony to imply two attitudes. The subject matter of these two statements can reduced to its simplest form and stated as: the evils of Emma's life. This is a serious subject, especially when coupled with the vocabulary word (vocabulary use is a subcategory of grammar: words and word usage) "danger." With this topic looming from the first phrase, "The real evils," we expect a serious danger to obtrude into Emma's life. Instead, we encounter verbal irony as we are told that the dangerous evil of Emma's life is that she is over-indulged, pampered, unguided and spoiled. The technique Austen uses here is juxtaposition of the serious with the ridiculous (though too true) in one statement. When we read that the evil facing Emma is that she is spoiled, we have to laugh and understand the ironic tale about to unfold (or we are confused because we have never encounter a heroine who is maligned and painted in unpleasant shades at the outset).
We've already noted one point in grammar, that being the vocabulary choice, "danger." The phrase "threatened alloy" is a second vocabulary choice that reinforces the verbal irony of the two ideas in unexpected juxtaposition: being spoiled juxtaposed to danger and threat. Aside from some differences between 18th and 19th century punctuation and contemporary punctuation (e.g., the now unneeded commas in "at present so unperceived, that they did not" and "her own way, and a disposition"), Austen's grammar is perfect, thus, grammatically, vocabulary analysis is our best tool for understanding Austen's technique, though it is most likely Austen chose her punctuation to reinforce and emphasize her ironic statements.
Syntax--the arrangements of grammatical parts for style and emphasis of communication--adds strongly to the duality of Austen's ironic technique. Let's analyse part of the above quotation for syntax.
The real evils, indeed, of Emma's situation were ...; these were the disadvantages which threatened ...
Austen might have written the above thoughts using this syntax:
- The disadvantages that threatened were the real evils of Emma's situation which were ....
This is a straightforward statement that combines the subjects of the two semicolon coordinated sentences into one sentence. This syntax takes itself and its communication very seriously; there is no room for verbal irony in this syntax. This is a serious statement, and if Austen had written this instead or her two semicolon coordinated sentences, we would have had a very different image of Emma and our ironic tale of meddlesomeness and love would have been a serious didactic tale about a troublemaker.
Thus, it is through subject matter and unexpectedly juxtaposed subject matter; grammar and vocabulary; and syntax that Austen implies a different attitude than the essence of her narrative statements using verbal irony that she creates with these techniques. To find other examples, apply these steps of analysis to other ironic statements.