Valmiki Ramayana Ayodhya Kanda Sarga 34 Shloka 50
Original Shlokaअर्थितो ह्यस्मि कैकेय्या वनं गच्छेति राघव। मया चोक्तं व्रजामीति तत्सत्यमनुपालये।।2.34.50।।
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राघव O scion of the Raghu race, वनम् to the forest, गच्छ you may go, इति thus, कैकेय्या by Kaikeyi, अर्थितः अस्मि हि I have been asked, व्रजामि इति I shall go, मया by me, उक्तं च it has been promised, तत् that, सत्यम् truth (promise), अनुपालये I shall follow.
'O Rama, go to the forest', Kaikeyi had said, and I have given her word I would go. I must fulfil my promise.