"Good morning, my dear boy."
Translation:Bonjour, mon cher garçon.
I think that would be, "Bonjour, mon garçon cher." The word "cher" here, seems to have been used in a figurative sense.
Please do correct me if I'm wrong.
There are a number of words that take on an accent in the feminine form.
You just have to add them to the many things you have to remember in French.
Bonjour is hello or literally, good day. Since they specified "good morning", I did not think "bonjour" would work, and got it wrong.