Valmiki Ramayana Ayodhya Kanda Sarga 52 Shloka 54
Original Shlokaतव शुश्रूषणं मूर्ध्ना करिष्यामि वने वसन्। अयोध्यां देवलोकं वा सर्वथा प्रजहाम्यहम्।।2.52.54।।
1 source checked for this shloka
वने in the forest, वसन् while dwelling, मूर्ध्ना with my head, तव your, शुश्रूषणम् service, करिष्यामि will render, अयोध्याम् to Ayodhya, देवलोकं वा or the world of the gods, अहम् I, सर्वथा altogether, प्रजहामि relinquish.
As I dwell in the forest, I shall serve you with my head bowed. For this I may altogether relinquish Ayodhya or even heaven.