Valmiki Ramayana Ayodhya Kanda Sarga 21 Shloka 46
Original Shlokaतीर्णप्रतिज्ञश्च वनात्पुनरेष्याम्यहं पुरीम्। ययातिरिव राजर्षिःपुरा हित्वा पुनर्दिवम्।।2.21.46।।
1 source checked for this shloka
पुरा in the past, ययातिः Yayati, राजर्षिः rajarshi, दिवम् heaven, हित्वा having left, पुनः again, दिवम् इव like heaven, अहम् I, तीर्ण प्रतिज्ञः having fulfilled my vow, वनात् from the forest, पुनः again, पुरीम् to the city (of Ayodhya), एष्यामि shall return.
Like rajarshi Yayati of yore who lost heaven and rejained it, I shall return from the forest to the city (of Ayodhya) after the vow is fulfilled.