Since we have nothing better to do then talk and speculate for the next 2 months *snif* I guess I'll just tell you guys what's bothering me for a while now.

In The Crossroads of Destiny, Zuko had to chose between saving Aang or letting him die, and he chose to let him die by his sisters hand. If not for the Spirit Water, Aang would've been dead right now. If Aang would've been dead without the Spirit Water, which he would have been, since he said that Katara literally saved his life cause he was ''gone'', how the hell could Azula know all along that he was alive (and I'm talking about the time that Zuko spend in his palace at his fathers right hand). We all know that Azula wants her brother down on his knees, and giving him the ''honor'' for killing the avatar would've helped her with that, cause when people would find out that the avatar was alive after all, they would crucify Zuko.

Many of you would say that the Dai Lee were spying on Zuko and Katara when they were talking about the water after being thrown in the underground prison at Ba Sing Se, but I don't think that Azula would think that this ''spiritual water'', which might heal a scar, would be able to save someone's life by bringing someone back from the dead. You shouldn't forget that all she would have heard, if she DID send some Dai Lee agents over there to spy on them, was that this special water had a small chance of healing Zuko's scar... I guess it's needless to say that there's a pretty big difference between healing a scar and bringing someone back from the dead.

What do you guys think?

Because she's magical. No, seriously, this sounds about right to me:

How did Azula know?

Has anyone seen Zuko's poker face?

You have all made good points about how she could have reasoned it out from Zuko's lingering doubts but arn't you also forgetting that all along they had no body?

She knew full well that thanks to Iroh, Katara was able to escape with Aang's body so whilst she might reasonably assume her direct hit with a lightning bolt should have killed him, without a body she had to entertain the possibility that it wasn't quite that clear cut or somehow they might save either through healing or some hitherto unknown avatar ability that makes him harder to kill.

Don't forget she also lied to the Fire Lord and told him it was Zuko that dealt the killing blow, why would she do this unless she suspected he might have survived or as a means to control Zuko (assuming it was more than just sisterly love as she claimed).

I don't think she knew exactly. I think she just suspected it.

She could have known through two ways or both. Since Zuko suspected that Aang was alive, she may have read this of him. Or she's just paranoid and decided to give Zuko that honour, just in case. Or like I said both.

Even if Aaang had died, I still think she would still put that plan into actions. Probably because Azula doesn't like taking chances. She's always sure.