I would ...
* prepare two big (organic) carrots for Santa's reindeers and leave a nice note along to welcome them to our home
* bring some comfort to Santa by filling a cup with milk and putting a biscuit (only one as I'm a bit concerned about Santa's big belly) under the tree
* not question the possibility to bring a bicycle through a chimney flue
* be happy to get a big little ribbon curl I could then tie around my rabbit's neck
* sing (again and again!) Christmas songs with my lovely voice
* try to convince myself I've been a nice little girl, forgetting about teasing from my brothers and my shouting
* wish to see Santa. I'd just like to go and see his house and his workshop, and ride in his sleigh, and know Mrs. Santa
The little girl knows Santa will come, because--well, because it's going to be Christmas Eve, and because he always has come to leave gifts for her during all the other Christmas Eves that she can remember.