。
She is very polite.
Literal
She [topic-は] very manners-correct.
礼儀正しい literally reads 'etiquette-correct,' built from 礼儀 (manners, propriety) and 正しい (correct) — an i-adjective compound for someone whose conduct hits the right notes. 礼 (rei, ritual courtesy) is one of the central virtues inherited from Confucian ethics, which left a deep mark on how Japanese society codifies politeness, from greetings to the careful keigo register.