I feel this song touches on insecurity in relationships. She is obviously saying that despite what one person in any given relationship may say, the other person may continue to feel that there is reason to doubt how the other person feels about him/her. Alicia Keys is saying that insecurities need to be set aside, because "I Need You". She is saying that she cannot understand why the other person is insecure because to her, they are a perfect fit for each other despite their differences.
I feel this song touches on insecurity in relationships. She is obviously saying that despite what one person in any given relationship may say, the other person may continue to feel that there is reason to doubt how the other person feels about him/her. Alicia Keys is saying that insecurities need to be set aside, because "I Need You". She is saying that she cannot understand why the other person is insecure because to her, they are a perfect fit for each other despite their differences.