The Book Thief, what does liesel’s relationship with rudy teach liesel about herself? why does she kiss him in the end

Rudy is somebody who a lot of girls would say is the sweetest guy in the world. He gives without hesitation and stands up for what he believes in regardless of the consequences. I think Liesel learns this from him. Liesel finally realizes, a little too late, that she loves him (hence the kiss).