I believe in soul mates. Your twin soul somewhere out there, or perhaps already in your life who connects with you the most, understands you the best. But I don't really think it has to be your beloved, or someone you are romantically connected to. It can be anyone- your best friend, your brother or sister, parent, or someone you're acquainted with.
That person is special. She accepts you as you are no matter what. She loves you for who you are. She brings out the best in you. You don't feel the need to suppress your own real self around her. You don't feel the need of any facade to save you around her. You can just be 'You'. She brings in positive changes in you. And you realize the absence of her in your life creates an irreplaceable emptiness, a void that cannot be filled by anyone else. You can recognize her when she walks into your life.
"We don't meet people by accident. They are meant to cross our paths for a reason."
I have been fascinated about twins- one soul inhabiting two different bodies. Perhaps they are the lucky soul mates, as they are born of the same mother. Reading 'The thirteenth tale' and watching the Thai movie 'Alone' has made me too curious about that special equation that twins share. In the book, the protagonist knows something is missing in her life, that uncomfortable feeling, but doesn't know what until she finds out about her twin who couldn't survive long and had died just after birth. And in the movie the girl has the uncanny feeling of her conjoint twin's presence, even after her death.
Perhaps that's my idea of soul mates- being able to sense each other and have a bit of telepathy. :)