What does Mae share with Winnie that encourages her not to be fearful of the Tuck family?

In chapter 6, Winnie is kidnapped by the Tuck family as she is about to drink from the spring. The family plead with her not to be frightened of them. They promise her that they wouldn't harm her "for the world." Winnie, meanwhile, feels her heart "pounding," and her mouth becomes "dry as paper." She starts to think that she "might never see her mother again," and with this thought in her mind, she begins to cry.
In response, Mae assures Winnie that they, the Tuck family, are "not bad people." Mae also takes out a music box and winds the key so that the music begins playing. This music, described as a "twinkling little melody," somehow calms Winnie. The Tuck family then tell Winnie that eighty-seven years ago they drank from a spring which gave them eternal, immortal life. They also explain how miserable it is to live forever. Mae takes up the story and tells Winnie that they kidnapped her to stop her drinking from the same spring. Mae tells Winnie that if she had drank from the spring, she would now be "a little girl forever . . . never (to) grow up, not ever." By telling her this, Mae hopes to make Winnie realize that the Tuck family mean her no harm—in fact, they are only trying to protect her from the misery of eternal life that they have become accustomed to.