Thanks for giving me the opportunity to read your manuscript.

I really enjoyed GRANDMASTER DRAW. You're very talented -- I found the writing natural, atmospheric, and evocative and it grabbed me right away. This was one of the most distinct submissions I have read in some time. Unfortunately, all of the elements just didn't all come together for me in the manuscript, and I had a harder time getting into the story than I would have liked. For that reason, I'm going to have to pass.
As you know, these decisions are highly subjective and another agent will likely have a different opinion.

I want to reiterate that I think you're very talented and I would be very pleased to receive submissions from you in the future. In the meantime, I wish you the very best in finding a good home for your writing.

Kind regards,

Thanks. Think of it as a note of encouragement rather than a rejection.
You have many great things ahead of you.