Honesty refers to how correct a Perspective is as evaluated by the subject that holds the Perspective.
Honesty as a value guides any given subject to maximize the correctness of the Perspectives they hold. Note that the same subject is evaluating that correctness, this is a key concept.
Note that correctness isn’t listed as a value. Correctness is relative and not measurable (just like absolute time isn’t measurable in general relativity). We value measurability enough that we discard correctness as a potential value and replace it with honesty, instead, which specifies that the correctness is evaluated specifically by the subject that holds the Perspective.