agree _verb

1-) have the same opinion

ADVERBS

heartily, strongly, very much
・I strongly agree with your proposal.

absolutely, completely, entirely, fully, wholeheartedly
・You're absolutely right, I completely agree with you.

genuinely, sincerely
・He genuinely agrees with the idea.

definitely, certainly
・I definitely agree with your conclusion.

broadly, generally
・While I have a few reservations, I generally agree with your proposal.

unanimously
・The board of directors agreed unanimously to implement the new cost-saving measures.

gravely, lamely, meekly, soberly, tartly
・I gravely agree that climate change is a pressing issue that requires immediate action.

VERBS

cannot
・They cannot agree on which movie to watch tonight.

be inclined to, tend to 
・I'm inclined to agree with you, at least in most aspects.

PREPOSITIONS 

with
・I agree with your assessment of the situation.

about 
・They couldn't agree about the best way to solve the problem.

on/upon 
・It's important to agree on the terms before signing the contract.

PHRASES

I couldn't agree more
・I couldn't agree more with your opinion on this matter.

2-) say yes

ADVERBS 

reluctantly, grudgingly • voluntarily
・After much persuasion, she reluctantly agreed to join the team.

readily • kindly
・They readily agreed to help with the charity event.

tacitly • implicitly
・She didn't protest, which meant she tacitly agreed to the arrangement.

provisionally
・He provisionally agreed to attend the event, but his schedule might change.

PREPOSITIONS

to
・They agreed to the proposal for increased funding.

3-) come to an understanding or agreement

ADVERBS 

expressly • tacitly
・She expressly agreed to support the charity.

verbally • provisionally
・The manager verbally agreed to the extra day off.

finally, eventually
・They finally agreed on a restaurant for dinner.

VERBS

be unable to, fail to
・They were unable to agree on a solution.

PHRASES

agree to differ/disagree
・It's better to agree to differ instead of arguing endlessly about minor details.

(be) mutually agreed
・After some negotiation, we mutually agreed on a new schedule.