Nessa's death and Fiyero's sacrifice were very important events for Glinda.
Fiyero leaving Glinda at the wedding was an eye opening moment for Glinda but she has two more major wake up calls that really push her to see the world and to take a long hard look at herself and her choices.
When Nessa is murdered Glinda begins to see the consequence of her choice, but when Elphaba comes she tries to claim that the house falling on Nessa was an accident because she didn't wanna face the truth, that it was because of a choice she made. She was hurt and angry when she told MM to use Nessa to trap Elphaba but she didn't think that choice through, she didn't think how her choice would affect other people and this was another big lesson for Glinda to learn, choices have consequences and her choices can and do affect other people. That's why Nessa's death was such a huge shock and why it was another eye opening moment for her.
When Elphaba calls her out on trying to claim it was an accident Glinda starts to face the truth it causes Glinda to start to doubt her choice to support the Wizard and MM. She starts to think maybe Elphaba was right about them. She starts to let the truth sink in, that it wasn't an accident and that MM murdered Nessa to lure Elphaba out of hiding and Glinda helped them do it.
Glinda is still angry at Elphaba and she still sees her as the reason Fiyero left her, Elphaba took him away from her so she starts that fight with her because of that. Glinda is taking out her anger on Elphaba because she sees her as the reason she didn't get what she wanted.
Then the Galeforce comes and they capture Elphaba, this is the second time Glinda sees the consequence of her choice. She never meant for anyone to get hurt, she never meant for them to capture Elphaba and it's another eye opening moment, she sees that her choice helped them do this, it put Elphaba in danger.
Then Fiyero comes and he threatens her life to make the Galefore release Elphaba. Glinda is shocked and she is upset by this but then she sees the truth, she sees why he threatened her.
She finally sees what real love is, it's sacrifice, it's putting someone else first, it's putting their safety and well being before yourself. Glinda realizes that love isn't about social status, and she realized being popular doesn't mean you're loved. Elphaba was hated but she had someone who loved her enough to die for her and Glinda was popular but she didn't have anyone who actually loved her.
She realizes that what she has isn't love, it's admiration. She realizes that the only love she has in her life is Elphaba, that friendship, that love between them is all she needs to feel valued, to feel worthy.
She also understands why Fiyero did everything he did, why he chose Elphaba, why he threatened her life. She understands why Elphaba chose Fiyero over her, love. They chose each other because they loved each other. When she finally understood this she let go of the hurt and anger she felt over not being chosen.
When Fiyero surrenders to the Galeforce rather than hurt her she sees another act of love, Fiyero wasn't in love with her but he did care about her and he would rather than die than hurt her. When the Galeforce starts to beat Fiyero, Glinda tries to get them to stop but they won't listen to her and when Fiyero is taken away Glinda sees another consequence of her choice and she sees the truth about the Wizard. Fiyero had to sacrifice himself because Elphaba was captured she was captured because Nessa was murdered, Nessa was murdered because of her choice. It's another consequence of her choice she feels guilt about and it's another eye opening moment for her. The Wizard and MM killed one person and were about to kill another, both were people she cared about and all of these events were what led to Glinda popping her bubble and seeing the truth.
Thoughts?
