Good question. They are very similar and writers like to play with their meanings, but they have their own uses. Consent- You allow it. A common use would be "consent to a background check for a job". More passive than the others. Accept- Very similar to consent. You allow something to be given to you, or to happen. For example, you accept an award for hard work, or accept that your friend disagrees with your opinion (but you still want to be friends) Agree- Like consent, but more affirmative. You can agree to a date because you want to go, or you agree with an opinion because you believe that it is correct. Sometimes people will use "agree" like a stronger "accept". Confirm- This is different in use. When you repeat a piece of information to show that it is correct, you confirm it. For example, if someone asks you if Friday is your birthday, and you say yes, you have confirmed that Friday is your birthday for them. This one can be tricky though. If my boss asks me to work this weekend and I say yes, then I agreed. If they ask later because they do not remember, and I say "yes, I'm working this weekend', then I confirmed it.

Agree is to show willingness with someone opinion And accept use for terms and conditions like you accept your job agreement