What do I say in a restricted donation letter?

I am accepting a collection of dolls and stuffed animals that are worth money and I am to give them directly to children or if there is an auction then the proceeds are to be used for children. What should I say in the letter?

What children are you trying to reach?

We can't help you without knowing more about your not for profit organization.
But generally you can just say what you said here, although you should specify something about the needs of the children, so that you don't just give them all to your daughter and her friends.

"Thank your for your generous donation of dolls and other toys. As you stipulate, we will guarantee that they are all either given directly to a child within our organization's area, one each, or that the proceeds from an auction will be used for our programs for children."

Is this a registered non profit group ? What country is it at ?