ἰσχυρίζεσθαι
From LSJ
καὶ νῦν ἀτεχνῶς ἐθέλω παρέχειν ὅ τι βούλει σοι, πλὴν κωλακρέτου γάλα πίνειν → and now I want to provide you with absolutely anything you want, except paymaster's milk to drink
Greek > English (Woodhouse Verbs Reversed)
(see also ἰσχυρίζομαι): affirm, assert, assert confidently, assert dogmatically, assert emphatically, assert positively, assert vigorously, base one's confidence on, contend that, maintain an opinion, press one's views, protest in argument, take one's stand on, trust to, urge strongly