Knightley, plain-spoken and fair, diagnoses the danger of flattery and self-regard. He is speaking about Emma’s interference with Harriet’s match, but the line applies broadly: vanity distorts judgment. The balanced clause turns moral counsel into a compact rule. Its slight severity shows Knightley’s role as Emma’s truth-teller—he loves her enough to risk displeasing her. For Emma, this is an early warning she brushes aside; later events prove him right. The maxim also captures Austen’s ethical world: harm often begins not in cruelty but in self-deception. Emotionally, it registers as tough love—steady, protective, and corrective. The reader senses the seed of partnership here: honesty as care.