Let someone down.
让某人失望

I have faith in you. Do not let me down.
我相信你。不要让我失望。
I consider myself as a reliable partner who never let others down.
我认为自己是个可靠的伙伴，从不让别人失望。
Another of my fears was that of letting someone down.
我恐惧的另一件事情是让别人失望。
I am afraid that this time, I will let you down.
恐怕这次我要让你失望了。
"I do not want to let you down."
“我不想让你失望。”

快快发给好友，随学随用！