She and Luke send letters to Santa every year, and when her return letter arrived from the North Pole, she sat down to write him again. This time she thanked him for writing her back, and for bringing all the girls and boys presents and for being so kind.
Here is a great book I recommend to all parents to help kids understand who Santa is/was and why he's a part of Christmas: (Grace has read this many times.)

This is the review on Amazon.com
In Santa, Are You For Real?, children will discover that there really was a Saint Nicholas. Through colorful illustrations and a heartwarming story, children - and parents - will learn who the real Saint Nick was, when he lived, and why he gave gifts. Most importantly, you'll see how the original Saint Nick set an example for us today by keeping Christ at the heart of Christmas.
Written by Harold Myra, President of Christianity Today, Inc., this trustworthy story is accompanied with fun, whimsical illustrations.
In Santa, Are You For Real?, children will discover that there really was a Saint Nicholas. Through colorful illustrations and a heartwarming story, children - and parents - will learn who the real Saint Nick was, when he lived, and why he gave gifts. Most importantly, you'll see how the original Saint Nick set an example for us today by keeping Christ at the heart of Christmas.
Written by Harold Myra, President of Christianity Today, Inc., this trustworthy story is accompanied with fun, whimsical illustrations.
Merry Christmas everyone! Enjoy your family traditions together. Share the JOY.