Valmiki Ramayana Yuddha Kanda Sarga 91 Shloka 8
Original Shlokaइत्युक्त्वारावणसुतोवञ्चयित्वावनौकसः । प्रविवेशपुरींलङ्कांरथहेतोरमित्रहा ।।6.91.8।।
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अमित्रहा slayer of his enemies, रावणसुतः Ravana's son, इति thus, उक्त्वा having spoken, वनौकसः to Vanaras, वञ्चयित्वा deceiving, रथहेतोः for getting the chariot, लङ्कांपुरीम् Lanka city, प्रविवेश entered
Ravana's son, a slayer of his enemies, having spoken to Vanaras in that way, in deceiving manner entered Lanka to get the chariot.