There is no corresponding word in this Japanese proverb, which is actually added by the translator to distinguish the characters with strong personality from others in the original plot.

For example, in The Silver Soul, she likes to add "でぁる" to every sentence. This word has no meaning in Japanese. If translated into Chinese, the personality of Shenle cannot be displayed, so a "moral theory" is added.

Then Dick Gumshoe reversed the referee. He likes to add っす at the end of every sentence. This is the sound change of です, which is also meaningless. Therefore, in order to distinguish his speaking style, the word "morality" was added to the Chinese translation.

So LZ's sentence "It's a beautiful day today" may be the translation of "Today's Day".