Make certain (of) synonyms
To test by carefully questioning in order to find out the knowledge, skill, qualifications, etc. of (a student, witness, job applicant, etc.)
Guarantee is defined as to state with confidence that something will happen.
To announce one's arrival (at a hotel etc.)
Find another word for make certain (of). In this page you can discover 6 synonyms, antonyms, idiomatic expressions, and related words for make certain (of), like: make sure of, find out, investigate, examine, guarantee and check-into.