It is better to truly know someone and love him or her than to "love" someone you don't really know. Shakespeare's sonnet 130 takes on the numerous love poets before him who exaggerated the positive qualities of a woman so much that no woman could possibly compete. Women are wonderful, yes, but we're not goddesses. We "tread" upon the earth; we don't float over it. No one actually has skin as white as snow. We're ruddy or olive or dun coloured. As for our breath--let's face it, not many women exhaled breath as sweet as perfume when they spoke, especially given that toothpaste and mouthwash were not standard items in the average Elizabethan's water closet. In fact, neither were showers, nor even frequent baths. As for the sound of our voices--isn't it more about *what* someone says than *how* she says it? He says he "loves to hear her speak" and yet he is aware that the quality of her voice doesn't compete with music. Whose does? I've heard a lot of women speak, and none of them have had such a stunning voice that I'd rather listen to that than a symphony; not that it matters, anyway, for what I really care about is the content not the outside appearance. This is what I take to be the point of the sonnet: it's what's under the surface that counts. All of these other women pale in comparison because the terms the poets have chosen to describe them are inflated and, therefore, false. If you really love someone, you see that person for who she is, flaws included, and still love.
To put it simply, the theme is that "beauty is in the eye of the beholder" and/or, perhaps, "love is blind."
The sonnet appears below, and my analysis in brackets underneath lines as necessary:
My mistress' eyes are nothing like the sun;
(Favored eyes as far as beauty goes, tend to be bright. Her's are dim.)
Coral is far more red, than her lips red:
(Red lips were the fashion, and indicate health, but hers are pale like coral.)
If snow be white, why then her breasts are dun;
(Albaster white skin was favored in Shakespeare's day, but hers is yellowish. He chooses her breasts in particular to which to make this unflattering comment, further reducing her appeal as a woman.)
If hairs be wires, black wires grow on her head.
(Yuck! The image conjures the mythical Medusa, not known for her feminine wiles...).
I have seen roses damasked, red and white,
But no such roses see I in her cheeks;
(Rosy cheeks indicated youth and beauty; she has none at all.)
And in some perfumes is there more delight
Than in the breath that from my mistress reeks.
(Bad breath too. Oh my.)
I love to hear her speak, yet well I know
That music hath a far more pleasing sound:
I grant I never saw a goddess go,
My mistress, when she walks, treads on the ground:
(He does not romanticize or idolize his lover.)
And yet by heaven, I think my love as rare,
As any she belied with false compare.
(The clincher: Despite all of her physical shortcomings, to the speaker, his lover is better than anyone he could compare her too. He loves her.)