Shloka 31
मनु-उपदेशः — भूत-उत्पत्ति, इन्द्रिय-निवृत्ति, तथा पर-स्वभाव-विवेकः
Manu’s Instruction on Elemental Origination, Sense-Withdrawal, and Discrimination of the Supreme Nature
तत्र यत् प्रीतिसंयुक्ते काये मनसि वा भवेत् | वर्तते सात्त्विको भाव इत्याचक्षीत तत् तथा,जब शरीर या मनमें किसी प्रकारसे भी प्रसन्नताका भाव हो, तब यह कहना चाहिये कि सात्विक भावका उदय हुआ है
tatra yat prītisaṃyukte kāye manasi vā bhavet | vartate sāttviko bhāva ity ācakṣīta tat tathā ||
毗湿摩说道：凡喜悦之感生起之处——或在身，或在心——若伴随真实的爱与满足，当知当言：此即萨埵（sattva）之显现，乃清明而善的德性。
भीष्म उवाच
Educational Q&A
A wholesome, sattvic state is recognized by the presence of sincere gladness or contentment arising in body or mind; such joy is a diagnostic sign of sattva’s predominance.
In the Shanti Parva’s instruction on conduct and inner qualities, Bhishma is explaining how to identify the guṇas in lived experience, here giving a practical marker for sattva.