I was afraid of what it would make me.
I told Aang that I wasn't sure about why I hesitated to take a life that should have been taken, and he understood. How could he not? Wasn't my situation exactly what he was going through?
I told Zuko the truth: I told him that I couldn't kill the man who so righteously deserved to die. He too, understood, and said that my choice made me strong.
I told him what I didn't tell Aang; that I didn't kill him because I was afraid of guilt, of conviction. I was afraid to be known as a killer, like him. I was afraid of everything.
If I was supposed to be so strong, then why wasn't I able to stop a single tear from falling down my face? Some strength.
Somehow, Zuko made me feel stronger after he wiped away that tear (as well as the few that followed), and drew me into a hug.