Which term best describes an action of confirming or validating something by repeating it?

The term that best describes the action of confirming or validating something by repeating it is "Reiterate." To reiterate means to say or do something again, often for the purpose of emphasis or clarification. This repetition can serve to confirm the original meaning or intention behind a statement, making it clearer or more authoritative. In contexts such as communication or instruction, reiterating key points can help ensure understanding and retention among listeners or readers.

Reaffirm typically implies a formal confirmation or declaration of support for something, often in a way that strengthens the original statement rather than merely repeating it. Remark simply involves stating or mentioning something casually without the connotation of repetition for validation. Review entails examining or assessing something again, which may not necessarily involve repeating a statement as a form of validation. Thus, reiterate is the most precise term for the action of confirming by repeating.