If translating french to english, marc becomes mark.
Following your logic, "James" should become "Jacques", and I refuse to call the 007 agent Jacques Bond! ;)
Some people tend to be picky when their names are translated, but yeah, the equivalent of Marc in French is Mark in English
I would think we would talk about Marc being masculine that's why we use “ami”
Mark is the most common spelling in English, but I got it wrong for spelling it with a k.
Is it always Mon ami(e) because the ami(e) seems to be associated wih the gender of the name and so far it has always been mon. Will it ever be ma?
For euphony reasons, ma becomes mon in front of a vowel sound. Some example with feminine nouns : mon épouse, mon horloge, mon interrogation.