Valmiki Ramayana Sundara Kanda Sarga 13 Shloka 49
Original Shlokaरावणं वा वधिष्यामि दशग्रीवं महाबलम्।।5.13.49।। काममस्तु हृता सीता प्रत्याचीर्णं भविष्यति।
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वा or, दशग्रीवम् tenheaded one, महाबलम् endowed with great strength, रावणम् Ravana, वधिष्यामि I will, हृता dead, सीता Sita, कामम् अस्तु desire will be fulfilled, प्रत्याचीर्णम् fitting reply, भविष्यति will be.
"I will kill Ravana, this mighty, tenheaded demon. Sita was indeed carried away by him. This (killing him) can be a fitting reply to his evil action. My desire would be fulfilled.