STEP Greek Lexicon: πιστόω

πιστόω, -ῶ

(πιστός), [in LXX chiefly for אָמֵן ni. ;]

to make trustworthy (Thuc., 3Ki.1:36), hence, to establish (1Ch.17:14). Pass. and mid., to be assured of: with accusative of thing(s), 2Ti.3:14.†

(AS)