Canto 3 -
Araṇya-kāṇḍa
Chapter 10: Rāma Asserts His Unbreakable Resolution to Fulfill His Promises

Rāma praises Sītā and informs her that when the sages had surrendered unto Him, He had promised to kill the rākṣasas obstructing their asceticism. He also tells her that fulfilling His promises is more important to Him than even His very life. Therefore, He will certainly do what He had promised these sages.