The word "一诺千金" is formed by combining four characters: 一 (one), 诺 (promise), 千 (thousand), and 金 (gold). Literally, it means "one promise, thousand gold", where a numerical contrast between "one" and "thousand" directly amplifies the value of a promise by equating it to a large quantity of gold, thus creating a figurative expression that emphasizes the immense worth of keeping one's word.