"If you want a long-term relationship" suggests that building a lasting partnership requires certain principles and behaviors.
"Follow one simple rule: never lie" is the rule in question. It underscores the crucial role of honesty in maintaining trust and transparency between partners.
In essence, this quote distills relationship guidance into a concise and essential rule: maintaining a foundation of truthfulness is paramount for nurturing a long-lasting and fulfilling relationship. It emphasizes that trust is the cornerstone of enduring love and commitment.