chose promise, chose due

cosa promessa, cosa dovuta

The phrase "chose promise, chose due" can be translated to Japanese as: 「約束したことは守らなければならない」 (Yakusoku shita koto wa mamoranakereba naranai) This captures the essence of the phrase, which means "a promise made is a promise kept." If you prefer a more direct translation, it could simply be: 「約束されたことは守られるべきである」 (Yakusoku sareta koto wa mamorareru beki de aru)

promissa est, ob rem