确保 (què bǎo) is a transitive verb meaning 'to ensure' or 'to guarantee' that something happens, is true, or remains in a certain state. The first character 确 (què) means 'certain' or 'definite', and the second character 保 (bǎo) means 'to protect' or 'to maintain'. Together, they convey the idea of actively taking measures to make an outcome certain — not just hoping or assuming, but verifying and safeguarding it. It implies responsibility, intentionality, and often some degree of effort or procedure.

This word is commonly used in formal, professional, or instructional contexts — such as workplace safety guidelines, healthcare protocols, academic requirements, or technical documentation. It frequently appears with clauses introduced by that (that-clauses), often following structures like '确保 + [noun phrase] + [verb phrase]' or '确保 + [clause]'. While it can appear in spoken Chinese, it sounds more deliberate and authoritative than casual alternatives like 保证 or 让.