caturthe - in the Fourth Chapter; kahiluṅ - I have described; janmera - of His birth; mūla - the real; prayojana - necessity; sva-mādhurya - His own transcendental sweetness; prema-ānanda - of ecstatic joy from love; rasa - the mellows; āsvādana - tasting.

The fourth chapter describes the main reason for His appearance, which is to taste the mellows of His own transcendental loving service and His own sweetness.