What does Rebecca Nurse say about Betty’s condition in The Crucible?

Rebecca Nurse enters Betty Parris's bedroom, seeing the sick child, she is a calming, commonsensible influence, and just her mere presence seems to comfort the child. When Mr. Putnam asks if she'll come to their house and see if she can wake his daughter, Ruth, Rebecca says,

I think she'll wake in time. Pray calm yourselves.  I have eleven children, and I am twenty-six times a grandma, and I have seen them all through their silly seasons, and when it come on them they will run the Devil bowlegged keeping up with their mischief. I think she'll wake when she tires of it. A child's spirit is like a child, you can never catch it by running after it; you must stand still, and, for love, it will soon itself come back.

Rebecca has given birth to, and been grandmother to, a great number of children, and she is familiar with all the silly shenanigans children can get up to when it suits them.  Sometimes they just do things that are mischievous, and there is no really good reason for their behavior. Rebecca believes that Betty will be herself again, only when she feels like it, and Ruth Putnam too. When the Putnams tell her that Ruth will not eat, she says that it is likely that Ruth simply isn't hungry yet and will eat when she is. She believes the children's behavior has nothing to do with witchcraft and only to do with the fact that they are children.