φάντο

From LSJ

ὁ δὲ πείσεται εἰς ἀγαθόν περ → he will obey you to his profit, he will obey you for his own good end

Source

Russian (Dvoretsky)

φάντο: эп. (= ἔφαντο) 3 л. pl. impf. med. к φημί.