"That was the strange thing, that one did not know where one was going, or what one wanted, and followed blindly, suffering so much in secret, always unprepared and amazed and knowing nothing; but one thing led to another and by degrees something had formed itself out of nothing, and so one reached at last this calm, this quiet, this certainty, and it was this process that people called living."
The Voyage Out, Virginia Woolf
Oh, that's so Woolf-ish. Making the process of falling in love sound like the most painful and sorrowful thing.
Beyond that, in the bigger scheme of things, we don't KNOW until it happens. A vague sense of the future, perhaps, and a strong desire or effort to shape it a particular way, but we never really know, do we?