You'll know when it happens, you won't have to guess, All at once you'll find your heart is filled with happiness. You'll know when it happens, love can't be disguised, All at once the dreams you dreamed will all be realized. Your eyes will see things that are not really there. Your lips will say things, things you never would dare. You'll know when it happens, suddenly you'll say, "Darling, I'm in love with you," it happens just that way. Your eyes will see things that are not really there. Your lips will say things, things you never would dare. You'll know when it happens, suddenly you'll say, "Darling, I'm in love with you," it happens just that way.