Valmiki Ramayana Yuddha Kanda Sarga 121 Shloka 13
Original Shlokaअवश्यंत्रिषुलोकेषु न सीतापापमर्हति । दीर्घकालोषिताहीयंरावणान्तःपुरेशुभा ।।6.121.13।।
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सीता Sita, अवश्यम् surely, त्रिषुलोकेषु in the three worlds, पापम् sin, न अर्हति not done, शुभा auspicious, इयम् this, रावणान्तःपुरे in the gynaeceum of Ravana, दीर्घकालोषिताहि lived for log time
"That Sita is auspicious and has surely not done any sin is known to three worlds. But she lived long in the gynaeceum of Ravana."