WHEN BEFORE "{I LOVE YOU"|THOSE THREE COPYRIGHT|THAT PHRASE" BECOMES REAL?

That's the question weighing/lingering/racing in the minds of many lovers/couples/people. At what point does a simple expression/statement/declaration transform from something said/uttered/spoken out of courtesy/habit/passion into a genuine feeling/emotion/truth? Is it when your heart skips a beat/flutter/skip every time you see/look at/notice the