The phrase above doesn’t literally mean “the moon is beautiful, isn’t it?” in Japanese. It actually means “I love you”.
When the novelist Souseki Natsume (1867-1916) was an English teacher, one of his students translated the English phrase “I love you” as 我君を愛す | ware kimi o aisu. Soseki pointed out that Japanese people don’t say 愛す | aisu (to love), and that the best translation would actually be 月が綺麗ですね | tsuki ga kirei desune (the moon is beautiful, isn’t is?).
The more you know.....