Sanskrit
विषयेन्द्रियसंयोगाद्यत्तदग्रेऽमृतोपमम् । परिणामे विषमिव तत्सुखं राजसं स्मृतम् ॥ ३८ ॥
viṣayendriyasaṃyogād yat tad agre'mṛtopamam pariṇāme viṣam iva tat sukhaṃ rājasaṃ smṛtam
Translation
That which from the union of the senses with their objects at first is as nectar, but in the end is like venom, that pleasure is accounted passionate.
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Rajasic happiness runs the opposite direction: nectar at first, from the contact of the senses with their objects, and poison in the end. Placing this immediately after verse 37’s mirror-image structure is a deliberate rhetorical stroke — the two verses are built as a matched pair so the contrast lands without any extra commentary needed.