What is the basis of the quarrel between Henry, who is in disguise, and Williams?

When Henry says that he has heard that the king will not give himself for ransom, Williams remarks that once their throats are cut and they are dead, they would not know the difference. Henry counters that if he lived to see the king ransom himself, he would never trust him again. Williams tells Henry, still thinking that Henry is a commoner like he is, that it would not make any difference to the king at all if someone of his lowly status trusted him or not. It would have the same effect as trying to turn the sun to ice by fanning it with a feather.