一诺千金

a promise worth one thousand in gold (idiom); a promise that must be kept

each word carries weight; a promise must be kept (idiom)

one word worth nine sacred tripods (idiom); words of enormous weight

lit. once said, a team of horses cannot unsay it (idiom); a promise must be kept

to speak and keep one's promise (idiom); as good as one's word

one word worth a thousand in gold (idiom); valuable advice; words of enormous weight