Where is situational irony in the "The Necklace" and how does this convey the author's message?

In
situational , the outcome of an event is the opposite of what is intended.

Monsieur Loisel intends to bring his wife happiness through the invitation to the ball, which
was hard for him to come by, as well as giving her 400 francs for a new dress and advising her
to borrow a piece of jewelry from her friend Madame Forestier. Madame Loisel hopes to make
an...