'I love you'.is a citation not a declaration.

I love-you is without nuance. It suppresses explanations, adjustments, degrees, scruples. In a way – an exorbitant paradox of language – to say I-love-you is to proceed as if there were no theatre of speech, and this word is always true, has no other referent than its utterance: it is a performative.

And a tautology

I love you
Why do you love me?
Because I just do, why do you ask me that?  I love you because I love you.
But that is a tautology and if you canot explain why you 'love me' then the words
'I love you' are a citation, a quote.