Valmiki Ramayana Sundara Kanda Sarga 55 Shloka 9
Original Shlokaयदर्थमयमारम्भस्तत्कार्यमवसादितम्। मया हि दहता लङ्कां न सीता परिरक्षिता।।5.55.9।।
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यदर्थम् on account of what, अयम् this, आरम्भ: effort, तत् कार्यम् that work, अवसादितम् is foiled, लङ्काम् Lanka, दहता while burning, मया by me, सीता Sita, न परिरक्षिता हि not protected.
'My very mission is foiled. Sita has not been protected by me for no part of Lanka has escaped unburnt.