The person who is immune to the hero's press or reputation is in that position because (s)he sees (or saw) them in their personal life, when the mask is off, so to speak. Alfred is this to Batman, because he knew Bruce Wayne when he was a little boy who slept with a teddy bear and a nightlight and still sees the person behind the persona on a daily basis. Ma and Pa Kent would be this to Superman, because even though he's a superhero, he's also the boy whose diapers they changed and who they helped with his multiplication tables. Kato would be in this position to the Green Hornet, because, like Alfred, he sees the person behind the persona on a daily basis. Whether the hero actually matches up to his reputation or not is irrelevant to this trope.