That Nora doesn't commit suicide is due in no small part to Kronstad. He reminds her that even if she does choose to take her own life, he will still be able to ruin her posthumous reputation. Nora quickly comes to her senses, realizing that her husband and children can still be damaged by her fraudulent actions even if she's dead and buried. That being the case, she realizes that there would be no real point in taking her life.

Nonetheless, Nora's contemplation of suicide is highly significant in that it shows us that she has the makings of an independent woman. In order to contemplate suicide one must have developed a very profound sense of self, and that's exactly what appears to have happened in Nora's case. Although she claims to be contemplating suicide as a way of protecting her husband and children from scandal she's actually doing it to protect herself from the fallout over Krogstad's fraud.

This foreshadows Nora's famous final act in the play when she will slam the door behind her as she walks out on her family. In other words, what will effectively be an act of social suicide is prefigured by a contemplation of literal suicide. In both cases, Nora is asserting herself in a way that one would not have thought possible at the start of the play.

Nora considers suicide the only way out of the trap of Krogstad's control in which she and her husband are placed when Krogstad confronts her with what he knows.

When the play A Doll's House opens, Nora and Torvald Helmer are happy that Torvald has secured a new position which will provide them with more income. Before he became connected with the Mutual Bank, Torvald worked such long hours that he ruined his health. His physician told Nora that Torvald needed to spend a year in the south of Europe, but Torvald did not initially want to go. After he refused to spend the money, Nora claimed that her father lent her the money for the trip, and they left home. Eventually, Torvald recovered his health.

When the man who loaned her the money appears on the scene, life becomes more complicated for the Helmers. Called a "moral invalid" by Dr. Rank, Krogstad is guilty of forgery just as Nora is, who signed her father's name on the loan of money that she claims was given to her. Furthermore, Krogstad is the one who has loaned Nora the money. He also works at the bank where Torvald now works. Having been previously acquainted with Krogstad's moral character, Torvald dismisses Krogstad's character, as he was once caught in a forgery.

In act 2, Krogstad comes to the Helmer home and informs Nora that her husband has fired him; he also tells her he is aware that her father died three days before the date of his supposed signature on the promissory note. When Nora admits to having signed her father's name, Krogstad asks, "Didn't you realize that what you did amounted to fraud against me?" Now caught in a moral quandary, Nora contemplates suicide as she realizes that Krogstad can use her crime to blackmail Torvald into giving him a higher position instead of firing him. Krogstad, in turn, guesses at her thought. He warns her that her death would not stop him from getting what he wants. Also, he tells her, "your reputation would be in my hands," so her death would merely be an act of futility.

Nora considers attempting suicide at the conclusion of Act Two in A Doll's House as a two-fold measure to protect her husband, Torvald.

To understand this choice, we must first take a look at the events leading up to this moment: Nora has forged her father's signature on documents which enabled her to get a loan; this money paid for Torvald's "sick leave" (so to speak) in Italy. Torvald does not know the true origins of this money, believing that it has come directly from Nora's father. Only Krogstad, a disgruntled employee of Torvald's who has himself committed an act of forgery, knows the truth. After Torvald fires him on "moral" grounds, Krogstad blackmails Nora by leaving a letter with the details of her crime in Torvald's locked mailbox.

This brings us to the moment of decision. Knowing that Torvald will inevitably check his mail and read the letter, Nora considers death (again, for two reasons)...

First, she wants to protect Torvald from dealing with the tremendous shame and social consequences after he inevitably discovers her crime. Second, she believes her death will render her firmly out of the way of any of Torvald's heroic gestures to save her from social and moral ruination. 

Ultimately, Nora does not choose to kill herself. Torvald calls to her from the other room, "What's become of my little lark," and Nora runs to him "with open arms."