“Let me down.”
->실망시키다

Brad:Can you do me a favor today?
브래드: 부탁 하나 해도 될까?
Sam:I can try, what is it?
샘: 가능한 부탁이면, 뭔데?
Brad:I need to be at my appointment at 4:00 pm.
브래드: 오후 4시에 약속이 있거든.
Sam:That should be no problem, do you need a ride?
샘: 문제될 거 없겠는데, 태워다 줘?
Brad:Yes, and I can't be late, so please don't let me down.
브래드: 응, 늦으면 안 되거든, 그러니까 꼭 좀 들어줘.
Sam:Okay buddy, I'll be sure to pick you up early for your appointment.
샘: 좋아, 약속에 늦지 않게 데리러 갈게.