Gif and Jif are pronounced the same, with a soft g as in "gift" or "giant" because it's followed by a "i"
Everybody know the rule : a "g" in front of an "a", an "o", an "u" or a consonant is a hard g
While a "g" in front of an "e", an "i" or a "y" is a soft g
Also, as a french, it's in my right to be bad at english