Reason 5: When you have no fear about loving fully.
The last but not least of our reasons as it is, indeed, the most important one. The very REASON why you would NOT say "I Love You". "I Love You" put you in the greatest space of vulnerability. Each time you allow yourself to declare "I Love You" to another, you say: I am giving of myself.
Unless you know that you can give without counting because you receive from a limitless source, it is very frightening to let yourself be emptied.
BUT ON THE BRIGHT SIDE, first and foremost, make sure that you don't fear love so that you can soulfully and unconditionally say "I Love You".
I will love you, for the rest of my life.
p/s: I Love You. Enjoy the video. :))