Valmiki Ramayana 5.22.25

आनीतासि समुद्रस्य पारमन्यैर्दुरासदम् ।रावणान्तःपुरं घोरं प्रविष्टा चासि मैथिलि॥

ānītāsi samudrasya pāramanyairdurāsadam |rāvaṇāntaḥpuraṃ ghoraṃ praviṣṭā cāsi maithili ||

Our plain-language meaning of this verse is waiting for scholar review.