This is the 8372nd most frequent Japanese word.
志郎
"志郎" (Shirō) is a Japanese male given name meaning "aspiration" or "will" (志) combined with "son" or "young man" (郎).
In this sentence, '志郎' is used as a proper noun to refer to a person's name, specifically Mr. Shirō. The suffix 'さん' is an honorific indicative of respect.
志郎さんは優しい人です。
Shirō is a kind person.
Here, '志郎' is again a proper noun in the possessive form, indicated by the particle 'の'. It shows ownership, meaning the bicycle belongs to Shirō.
志郎の自転車が壊れた。
Shirō's bicycle broke down.
In this sentence, '志郎' is referred to in the context of discussing the name itself, underlining its significance and meaning as a proper noun.