A very easy way to protect the smiles of the townspeople is by killing the hero. Eliminate him and the king, paint him as the genocidal villain he is, then show them that only by following you can they be protected. Then they will start seeing you as the true hero and smile when you help them especially compared to a "hero" who skips the fight and has done nothing the whole time. Honestly the other magical girl is right, why bother with the humans who treat you as an enemy when you sacrifice yourself for them?