When do the words I love you become meaningless?

Texture and detail - I love.
I only thought about this so much today because someone said to me “When do the words I love you become meaningless? When can you say them so often that they lose their definition?”
They never do, do they? Those words never lose their ability to throw your heart into high gear and make you smile or shake loose those butterflies, as long as they are true. I just wonder how someone can not know when the words are false. Or how someone can hear the words, know they are false, but accept them as if they were truth anyhow.