Here, Irene is falling into the mindset that "passing" is done only to gain privileges and status by assuming that Wentworth would never think of sacrificing his white identity for that of a black man. After acknowleding that race is more than color, she ends the conversation by reducing the notion of passing to color. Also, while Irene cannot articulate any major difference between races earlier in the conversation, she states that it would be more difficult for a white person to pass as black, thus implying a tangible and apparent difference between their races.