Give me a promise

Give me a promise that I could never break and take from me the freedom to repel the make-believe I held to be true, until you; had I knew that sacrifice to save your life is no price at all for how I'd fall and fall and fall on every sword to see you from the blade. How could I have known to 'die for you' was not a promise to step before the shot, but how I could not live if I did not.