The phrase "makes sure" can be replaced with several synonyms to convey the same meaning, such as "ensures," "verifies," "confirms," "checks," "guarantees," "certifies," "ascertains," "affirms," "establishes," "corroborates," "validates," "double-checks," "inspects," "reviews," "examines," "scans," "scrutinizes," "proves," and "tests." These words indicate an action that is taken to ensure that something happens or is done correctly. Choosing the right synonym depends on the context and the level of certainty that is required to convey the intended message effectively.