信ずる
しんずる · shinzuru · JLPT N2 · verb-ichidan
to believe
信 = person (亻) + word (言): believing what a person tells you
信 combines 亻 (person) and 言 (speech, words), so it means trusting what someone says. ずる is the okurigana verb ending that makes it a verb.
信 — person 亻 + speech 言
信 combines 亻(person) with 言(speech), depicting a person standing by their words. The original sense is 'truthfulness' or 'sincerity'—what a person says can be trusted. From this it extended to 'believe,' 'trust,' and later 'message' or 'letter,' since a letter carries one's word.