The Sun-Neptune conjunction dissolves the clear boundaries of personality in the world of images, feelings, inspiration, and subtle states. The Sun wants to be a clear center, while Neptune brings mist, music, compassion, mysticism, dream, and ideal. Therefore a person with this aspect is often perceived as mysterious, soft, unusually attractive, or hard to read. There may be a feeling in them that their real "I" does not fit into ordinary words and roles.
Interpretation