Valmiki Ramayana Ayodhya Kanda Sarga 34 Shloka 28
Original Shlokaभवान्वर्ष सहस्राय पृथिव्या नृपते पतिः। अहं त्वरण्येवत्स्यामि न मे कार्यं त्वयाऽनृतम्।।2.34.28।।
1 source checked for this shloka
नृपते O king, वर्षसहस्राय for a thousand years, भवान् you alone, पृथिव्याः of this earth, पतिः are the lord, अहं तु as for me, अरण्ये in the forest, वत्स्यामि I will dwell, त्वया by you, मे to me, अनृतम् untruth, न कार्यम् should not be done.
You will remain the lord of this earth for a thousand years to come, O king As for me, I will dwell in the forest. Do not deviate from truth on my account.