Canto 3 -
Araṇya-kāṇḍa
Chapter 13: Rāma Departs for Pañcavaṭī
Text 3.13.5

एषा हि प्रकृतिः स्त्रीणामासृष्टे रघुनन्दन।
समस्थमनुरज्यन्ति विषमस्थं त्यजन्ति च॥

eṣā hi prakṛtiḥ strīṇām āsṛṣṭe raghu-nandana
samastham anurajyanti viṣamasthaṁ tyajanti ca

eṣā hi = it is indeed; prakṛtiḥ = the nature; strīṇām = of women; āsṛṣṭeḥ = from the beginning of creation; raghu-nandana = O beloved of the Raghus; samastham = a man in prosperity; anurajyanti = to love; viṣamastham = him in adversity; tyajanti = reject; ca = and.

O beloved of the Raghus, from the beginning of creation, it is indeed the nature of women to love a man in prosperity and reject him in adversity.1

GLOSS. Āsṛṣṭeḥ means īṣaj-janmanaḥ, “a little after their birth,” which means from the beginning of their second birth. The second birth of women is their marriage, since it is equivalent to Vedic initiation: strīṇāṁ pradāna-karmaiva yathopanayanaṁ tathā.1

1 Rāmāyaṇa-bhūṣaṇa: prakṛtiḥ svabhāvaḥ. āsṛṣṭeḥ jagat-sṛṣṭim ārabhya. samasthaṁ susthaṁ. prati viṣamastham durdaśāpannam. Rāmāyaṇa-bhāva-dīpa: āsṛṣṭe jagati. samasthaṁ mayā sampadā sahitāḥ samāḥ. teṣu tiṣṭhatīti samasthas taṁ sampad-yuktam anurajyanti anurāga-yuktā bhavanti. viṣamasthaṁ daridram.

1 In other words, from the beginning of their marriage, women love their respective husbands at times of prosperity and reject them at times of adversity, for this is their nature. This is a general principle. Of course, exceptions exist.