Canto 3 -
Araṇya-kāṇḍa
Chapter 18: Śūrpaṇakhā Disfigured
Text 3.18.13

इति सा लक्ष्मणेनोक्ता कराला निर्णतोदरी।
मन्यते तद्वचस्तथ्यं परिहासाविचक्षणा॥

iti sā lakṣmaṇenoktā karālā nirṇatodarī
manyate tad vacas tathyaṁ parihāsāvicakṣaṇā

iti = thus; = that; lakṣmaṇena = by Lakṣmaṇa; uktā = when was addressed; karālā = terrible; nirṇata-udarī = and fat lady; manyate = she considered; tat = those; vacaḥ = words; tathyam = to be conveying facts; parihāsa-avicakṣaṇā = as she was inexperienced in jokes.

When that terrible and fat lady was thus addressed by Lakṣmaṇa, she considered those words to be conveying facts as she was inexperienced in jokes.1

1 Why did Lakṣmaṇa joke with Śūrpaṇakhā thus? Because she was bewildered by lust, not by selfless love, for Rāma.