"You look like gold. I've been fooled before, but now I know I've made the mistake in the past. But now I, now I know the difference from gold and brass"

In this quote, Ben Harper is comparing somebody's appearance to gold, which is typically seen as an important and precious metal. He acknowledges that he has been tricked in the past by individuals who might have seemed important, however turned out to be phony or less valuable, like brass. Nevertheless, he has now found out to distinguish between the two and recognizes the real worth of this person. This could also be translated as a metaphor for relationships, where he may have been in relationships with people who seemed valuable however were not genuine, and now he has found somebody who is really important and worth his time and attention. Overall, the quote communicates a sense of development and gaining from previous errors.