assure
From LSJ
English > Greek (Woodhouse)
verb transitive
make sure or secure: P. βεβαιοῦν.
assert vigorously: P. ἰσχυρίζεσθαι, διισχυρίζεσθαι.
promise: P. and V. ὑπισχνεῖσθαι (τινί τι).
be assured (imperative): P. and V. ἴσθι, P. ἀκριβῶς ἴσθι, Ar. and V. σάφ' ἴσθι (also Xen., cyr. 5, 2, 32).
be assured: P. and V. σαφ' εἰδέναι (Ant. and Xen. but rare P.); see also learn.