The word “said” is usually the best choice when writing dialogue.
People choose “capitulated” or “sighed longingly” or “harrumphed”
but often the most powerful and most perfect choice is simply “said.”
That’s what I think about I love you.
I tell you I adore you (and I do)
I tell you I am completely in love with you (and I am)
but often the most perfect way to express the life-altering bliss you bring to my life is simply those three words.
I love you.