真实 (zhēn shí) means 'true, real' in the sense of being factual or actual, not fake or imaginary. It's more specific than 真 (zhēn), which is broader ('real, genuine' as an adjective; 'really' as an adverb). 真正 (zhēn zhèng) emphasizes 'genuine, authentic' (e.g., a true friend), while 真实 focuses on truthfulness to reality.