Here the "heart" represents the person's feelings or emotions. Alternate translation: "make me feel joyful" or "make me glad" (See: [[rc://en/ta/man/translate/figs-metonymy]])
Here "answer" does not mean to answer a question. It means to respond or to reply to someone who is mocking. How this relates to the clause before it can be made clear. AT "then I will reply to the one who mocks me by telling him about you" (See: [[rc://en/ta/man/translate/figs-explicit]])