I would love to do deep sea diving (if I could).
It expresses that the subject (upon reflecting on the matter) has decided that he/she wants to go deep sea diving, but it isn't implied that the subject has actually tried it, or ever will try it in the future. It is merely an idea.
I love to do deep sea diving implies that the subject definately does deep sea dive and loves doing it: it is an indicative sentence whereas the first is a hypothetical one.
I am not a teacher.