"Can I Keep You Forever" signifies the speaker's desire for the person to remain a constant and enduring presence in their life. It reflects the wish for a long-lasting and meaningful connection.
"That's All I Really Want" underscores the simplicity and purity of this desire. It suggests that above all else, what the speaker truly values is the idea of keeping the person they love close to them.
In essence, this quote beautifully encapsulates the longing for a lasting and meaningful relationship, where the speaker's greatest wish is to have the person they cherish stay with them forever, emphasizing the importance of love and commitment in their heart.