Shakespeare's Sonnet 131

Thou art as tyrannous, so as thou art,As those whose beauties proudly make them cruel;For well thou know’st to my dear doting heartThou art the fairest and most precious jewel.Yet, in good faith, some say that thee behold,Thy face hath not the power to make love groan;To say they err I dare not be so bold,Although I swear it to myself alone.And to be sure that is not false I swear,A thousand groans, but thinking on thy face,One on another’s neck, do witness bearThy black is fairest in my judgement’s place.In nothing art thou black save in thy deeds,And thence this slander, as I think, proceeds.

You are as tyrannical, just as you are, as those women whose beauty makes them proud and cruel. You know very well that to my loving, foolish heart, you are the most beautiful and precious jewel. Yet, honestly, some people who see you say your face has no power to make a lover sigh. I would not dare tell them they are wrong, although I swear to myself in private that they are.
And to prove that what I swear is true, a thousand sighs, just from thinking of your face, follow one another and testify that your dark looks are the most beautiful in my judgment. You are dark in nothing but your deeds, and I think that is where this slander comes from.