保证 (bǎo zhèng) is a verb meaning 'to guarantee' or 'to assure' — to make a firm promise that something will happen, be true, or be done. The character 保 (bǎo) means 'to protect' or 'to keep safe', while 证 (zhèng) means 'evidence' or 'proof'. Together, they convey the idea of 'providing assurance' — not just hoping, but actively ensuring an outcome. It's commonly used in formal and everyday contexts: making commitments at work, promising responsibility, or assuring quality or safety.

This word often appears with complements like 得 (de) or 不 (bù) to indicate ability or failure to guarantee, and it can take an object introduced by that (de) or a clause beginning with 一定 (yídìng). While it can occasionally function as a noun ('a guarantee'), its primary and most frequent use is verbal — expressing a binding commitment. Learners should note it’s stronger than 承诺 (chéngnuò, 'to promise') and carries more weight of responsibility and reliability.