Final answer:
The lines suggest that the mistake made was innocent rather than wicked, as the speaker admits to lacking judgment in an honest face.
Step-by-step explanation:
The lines "That errs in ignorance and not in cunning, / I have no judgement in an honest face" suggest that the mistake made was innocent rather than wicked. The speaker acknowledges that they lack the ability to judge a person's true character based on their appearance. This implies that the mistake was not intentional or deceitful, but rather a result of naivety or lack of knowledge.