Everyone has secrets. No exceptions.
Some secrets exist because of hope. Hope that things in the end will work out, or will simply come to be. Despite the logical flaws, the improbability of the situation or the scenario presented, hope floats as a beacon of delusions that mar better judgment, the decision to simply walk away or act upon it. So the secret remains hidden, shared to few if at all. The truth being the most effective lock to the proverbial Pandora's Box of failed aspirations, pain and regret.
Other secrets exist as a byproduct of goals, ambitions and agendas. Kept only to forward these clandestine goals. Such trump cards are used for devious and noble means. They can harm as well as they can protect, all dependent on the wielder's discretion. Knowledge is power after all, and even the most nonsensical fact and fleeting tidbits can prove vital given the right situation.
However, secrets are not predicated on those two alone. Shame, hate, pride and a bevy of human emotions are reasons enough to keep things hidden from others. Whatever secrets lay behind the minds of a man or woman, they are tucked neatly away because of fear, fear that the truth, the harsh and brutal truth will be known and the facade will be ultimately washed away.
Truth is not only the lock, but it is the key as well. As it is, secrets are truths, for good or ill. The deepest and darkest secrets are the truest and purest. Whether malicious or not, the honesty and the sincerity of such cannot be questioned.
Secrets when revealed are often amusing, shocking, if not downright sad. They explain many things, one's hopes, one's agendas and one's true intent (obviously). In the end however, the best secrets are those that can be said without Hope or Agenda, but simply said in all of it's honesty.
So to someone very special, this I say unto you, hoping and aspiring for nothing but for you to know, that I love you.
Sadly and perhaps fortunately, you'll never really know.