certain : (adj.) 1. niyata; nicchita; nissaṃsaya; 2. aññatara; ekacca.

A.P. Buddhadatta Mahathera, Concise Pali-English and English-Pali Dictionary [available as digital version from Metta Net, Sri Lanka]

rtogs par bya'o

[tenses]

• rtogs
• rtogs
• rtogs
• rtogs

[translation-san] {C} niṣṭā tatra gangtavyā

[translation-eng] {Hopkins} one should realize; one should understand

[translation-eng] {C} one can/should be sure/certain (that); should be quite sure

Jeffrey Hopkins' Tibetan-Sanskrit-English Dictionary