"Approve" is the most useful word. You can use it in a lot of situations. The other words are for specific situations. ratify + a treaty, a constitution, an amendment, etc. authorize + a transaction, a purchase, etc. This is a word for your boss, your bank, etc. "confirm" means to say something is correct or accurate. This is a formal word, less common in conversation. "validate" is similar but is more technical. validate a transaction (banking), validate the results of an experiment, etc. Also formal and uncommon in conversation.

ratify-means to give formal consent or to sign something. The world is used when you are talking about things are becoming official. Such as you are agreeing to a contract or signing an agreement. approve-to accept or to agree to. OR Think that someone or something is good or acceptable. This can also be used to give a more formal answer such as I approve of this new business proposal. OR I approve of your behavior. authorize-to grant authority to someone or give them power. For example, I gave him the authority to make the decision. confirm-means to establish the truth or to verify. I confirmed that we had bought tickets. validate-means to make valid. Valid means to be well-founded, or have weight. Such as I have a valid reason to to like that man. An example of validate is, His actions validated our suspicions. I hope that his helps.

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