Shloka 5.20.5
रावणस्य सीताप्रलोभनम् (Ravana’s Persuasion and Coercive Courtship of Sita)
स्वधर्मो रक्षसां भीरु सर्वथैव न संशयः।गमनं वा परस्त्रीणां हरणं सम्प्रमथ्य वा।।5.20.5।।
svadharmo rakṣasāṃ bhīru sarvathaiva na saṃśayaḥ |
gamanaṃ vā parastrīṇāṃ haraṇaṃ sampramathya vā ||5.20.5||
O timid lady, this is indeed the very dharma of the rākṣasas in every way, without doubt: to approach other men’s wives, or to seize them by force through abduction.
"O timid lady! having an unrighteous approach to wives of others or their abduction by force is natural to demons, There is no doubt.
The verse frames a direct conflict with dharma: violating another’s marriage and using coercion are admitted as adharma, even if the speaker tries to normalize it as a rākṣasa ‘nature.’
Rāvaṇa is pressuring Sītā in Laṅkā, attempting to justify his desire and threats by claiming such conduct is natural for rākṣasas.
By contrast (implicitly), Sītā’s steadfast chastity and adherence to marital dharma are highlighted against Rāvaṇa’s self-justifying adharma.