Help, Long Distance Relationship?

Iam in a LDR, I love my GF more than anyone else in the world, more than my own self. Whenever I say "I love you, and I won't be able to love anyone else more than friends."/ she says " I feel, you say that way because you're emotional." How do I tell her it is the fact, and I have been living the fact since 2+ years.. HELP!