There are multiple definitions - click on the translation that matches your context.

为他人担保

动词

full

vouch for

verb

Definitions of vouch for

English

to say that a someone has the qualities necessary for a particular task or position

My client was then driven to his hotel where staff were able to vouch for him.

English

to state that you believe something is correct or true; to say that you take responsibility for something

CBS has admitted that it cannot vouch for the authenticity of documents used to support the story.