Approval or agreement with a proposal or opinion; to support or be in favor of something (commonly used as 賛成する).
会議でその計画に賛成する人が多かった。
Many people at the meeting were in favor of that plan.
私はその意見に賛成だが、詳しい実行方法は議論が必要だ。
I agree with that opinion, but the detailed implementation needs discussion.
賛成と反対の意見を聞いてから決めよう。
Let's decide after hearing both the pros and cons.