I have an idea what happens to the princess you don't save.

[Big-Cat]

She gets possessed by one of the bosses. If you don't save Zelda, you'll encounter her being possessed by Ganondorf and then you fight him. For Peach, you have to fight her while she's possessed by the Shadow Queen and then you fight her. Overall, the possessed princesses will only have wardrobe changes.

 

[Red_Maniac]

So you made a new thread instead of looking for the old "what will happen to the princess you don't save" thread?

 

[Meta_Sonic64]

Or here's a better idea. They get devoured by Petey.

 

[Topaz989]

I like the Petey-eats-her theory better.

 

[Magnacor]

I'd say that another character saves her.

EDIT: Though I have to admit, the whole "Petey-Eats-Her" idea is cool. You were really thinking way outside the box on that one.

 

[Takeshi245]

You just made a thread to bring up a dead topic. Now your thread will eventually be closed. Use the search function next time so you don't have to waste your time like this. Have a nice day.