The word for ‘nosebleed’ in Japanese is Hanaji 鼻血, let us break down the term. The word hanadi can also be pronounced as hanaji because diぢ and ji じ sound very similar in the standard Japanese language.
Sailor Moon, Usagi Tsukino, is Japanese! While her blonde hair might be unusual, it's a common design choice in anime. The story itself is set in Japan, and the characters are all Japanese.