Valmiki Ramayana Ayodhya Kanda Sarga 109 Shloka 25
Original Shlokaस्थिरा मया प्रतिज्ञाता प्रतिज्ञा गुरुसन्निधौ। प्रहृष्यमाणा सा देवी कैकेयी चाभवत्तदा।।2.109.25।।
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मया by me, गुरुसन्निधौ in the presence of my father, स्थिरा firm, प्रतिज्ञा vow, प्रतिज्ञाता is sworn, तदा then, सा that, देवी कैकेयी च Devi Kaikeyi, प्रहृष्यमाणा अभवत् became immensely delighted.
I had taken a firm vow in the presence of my father (about my stay in the forest). And then Devi Kaikeyi was immensely delighted.