Canto 2 -
Ayodhyā-kāṇḍa
Chapter 9: Kaikeyī Convinced by Mantharā
Text 2.9.26

न ह्यतिक्रमितुं शक्तस्तव वाक्यं महीपतिः।
मन्दस्वभावे बुद्धस्व सौभाग्यबलमात्मनः॥

na hy atikramituṁ śaktas tava vākyaṁ mahī-patiḥ
manda-svabhāve buddhasva saubhāgya-balam ātmanaḥ

na hi = not; atikramitum = of transgressing; śaktaḥ = is capable; tava = your; vākyam = words; mahī-patiḥ = the king; manda-svabhāve = O inert woman; buddhasva = know; saubhāgya-balam = the strength of good fortune; ātmanaḥ = your.

The king is not capable of transgressing your words. O inert woman, know the strength of your good fortune.

“Know the strength of your good fortune” means “know the strength of your beauty.”