确实 is an adverb meaning 'indeed', 'truly', or 'in fact'. It emphasizes the truth or certainty of a statement, often used to confirm something previously mentioned or to express strong agreement. The character 确 means 'certain' or 'definite', and 实 means 'real' or 'actual'; together, they reinforce authenticity and factual accuracy. It frequently appears in spoken and written Chinese to add weight to assertions, especially in conversations where clarification or validation is needed.

This word is neutral in register—appropriate in both informal chats and formal writing—but is rarely used alone as a response; instead, it modifies verbs, adjectives, or whole clauses. It commonly follows subject–predicate structures (e.g., 他确实很努力) and can appear at the beginning, middle, or end of a sentence depending on emphasis. Unlike modal verbs or particles, 确实 doesn’t change form and never takes aspect markers like 了 or 过.