Valmiki Ramayana 2.109.24

कथं ह्यहं प्रतिज्ञाय वनवासमिमं गुरौ ।भरतस्य करिष्यामि वचो हित्वा गुरोर्वच:॥

kathaṃ hyahaṃ pratijñāya vanavāsamimaṃ gurau |bharatasya kariṣyāmi vaco hitvā gurorvaca: ||

Our plain-language meaning of this verse is waiting for scholar review.