I agree with you, and I think you have answered her to some extent. When do they really mean it when they say I love u? it depends on what kind of people they are. Some people are not good at express their love and once they say it, it is more probably he really meant it. And if someone easier speaks out  this word, and doesn't look serious, and loyal, then it is wiser not to believe.

i don't really understand your question.All i can say people use this word too way often, often they don't really mean it,  and it loses its importance...