I'd always prefer the honest path. You could try to explain the problem and why it might seem easier than it is in simplified terms. Also, fast and slow, hard

I'd always prefer the honest path. You could try to explain the problem and why it might seem easier than it is in simplified terms. Also, fast and slow, hard and easy - those terms don't always correlate. Easy tasks can require a lot of time while hard problems might result in a quick solution after careful consideration. Furthermore getting hard tasks done quickly might be exactly why you're billing that much. Maybe you've dealt with a similar problem before - in that case your experience and competence in that particular subject shouldn't devalue your work. What I'm trying to say is: Don't base your price on time spent alone.