Sincerity and truth are so important to me that I always keep them inside my coat (まこと). That's where I keep everything that's dearest to me, and what could be more important that sincerity and truth? Where do you keep sincerity and truth? I bet your answer is "my coat" too.
The film depicts the truth about samurai.
I’m sincerely upset that the judge accepted his plea of not guilty by reason of insanity.