Why a font appears different in Mac Os and Windows

Hi!

I have a font that appears differently in one OS than another.
In windows appears bold and in Mac Os, appears Regular font, although both have the same “Font family”.

Best,

Thanks Roel,

So a solution could be to add .TTF font to fonts directory?
Should it be named exactly as the font?
When I do F12 Developer mode, it looks like it had the font, but really it doesn’t.

How could I be certain the font is being applied correctly?