What is the "magic charm" that Hannah works on Kit in "The Witch of Blackbird Pond"?
The "magic charm" that Hannah works on Kit is nothing more than that she accepts her with kindness and listens with sympathy. By doing so, Hannah enables Kit to find peace and recognize that the answer to what she must do to fix the trouble she has caused lies in her own heart.
Because of her free spirit and willingness to use innovation in teaching the children, Kit has unintentionally gotten herself and Mercy fired from working at the dame school by Mr. Eleazer Kimberley, the schoolmaster. Immediately after this incident, Hannah finds Kit crying in the meadow, and invites her home to give her a chance to calm down and have a bite to eat. Hannah listens to Kit with a non-judgemental ear, and Kit pours out to her all the frustration she feels at not being able to fit into the life of Connecticut Colony, and her longing for her grandfather and her home in Barbados. Kit gains strength from Hannah's kindness and sympathy, and when it is time to go understands that Hannah, by showing her a single plant from Africa which has flourished in the new land despite its strangeness, has given her hope and confidence to carry on. Hannah tells Kit "the answer is in thy heart...thee can always hear it if thee listens for it", and Kit, taking courage, leaves to make things right with the schoolmaster (Chapter 9).