The person who you know.
The person that you fall in love with.
Who you are the whole-hearted to.
The funny one.
The smart one.
The one that could always cheer you up.
Remember in the movie City Slickers when our favorite cowboy is about to find out the meaning of life but then the one with the knowledge to pass on about what the "one thing is" keels over first? That's how finding the One is. You die before you find out who it is. Or die trying! Or try not to die?