How do you say §509合意に達するのは難しく無かろうという情報とは異なり、我々は大変苦労したのだ。このことで我々は、交渉は思っているほど簡単には成功しないということを学んだのだ。 in English?

Unlike the information that we would have no difficulty in reaching the agreement, we had a lot of difficulties, which made us learn that negotiating is not as easy to be successful in as we thought.