श्वस्śvas(सम्) happiness, prosperity.
Derived forms and compounds
आश्वासयामास च भीतमेनं
कोशःDictionaries
V. S. Apte, The Practical Sanskrit–English Dictionary. Look up any word of the Gita in Devanagari, IAST or Harvard-Kyoto, or browse the headwords letter by letter.