Canto 2 -
Ayodhyā-kāṇḍa
Chapter 26: Rāma Meets Sītā and Instructs Her
Text 2.26.28

अहं चापि प्रतिज्ञां तां गुरोः समनुपालयन्।
वनमद्यैव यास्यामि स्थिरा भव मनस्विनी॥

ahaṁ cāpi pratijñāṁ tāṁ guroḥ samanupālayan
vanam adyaiva yāsyāmi sthirā bhava manasvinī

aham ca api = I; pratijñām = promise; tām = the; guroḥ = of My master King Daśaratha; samanupālayan = fulfilling; vanam = to the forest; adya eva = immediately; yāsyāmi = will go; sthirā = fixed in your affection for Me; bhava = be; manasvinī = as a lady of firm mind.

Fulfilling the promise of My master King Daśaratha, I will immediately go to the forest. As a lady of firm mind, be fixed in your affection for Me.