how does the main character develop or grow as a result of the incidents in the story?

GradeSaver has a really good summary of how Liesel grows. Check this out,

Ultimately, Liesel learns the power of words to influence humans to act towards both good and evil as she experiences the beauty and the brutality of humanity. Death describes her as a "perpetual survivor," and Liesel survives Hitler's reign while many of those whom she loves perish as a result of World War II and the Holocaust.

I did read the book and much of the theme impresses on Liesel. She learns, through the power of words, the incredible power an individual can yield. Her innocence is taken away at a young age and she quickly learns what to stand up for. Death, our narrator, even thinks she becomes a tough self-aware girl. That's pretty good because I could imagine Death would be kind of a downer to be around!