J2 looks sad. She stands in front of me and says, "Mommy, I'm sad. [J1] is going to tell her friends that I don't like cake. And I do like cake!! I don't want her to tell her friends that."
I tell her, "You know you like cake, right? So I wouldn't really worry about what your sister's friends think of your cake preference."
Then she nodded very solemnly at my sage advice.