And yet, by heaven, I think my love as rare
As any she belied with false compare.
His lover isn’t some ridiculous dream-creature; however, he loves her and sees her as beautiful nonetheless. He is swearing by heaven that his mistress is superior, in his eyes, to any woman whose beauty is falsely enhanced by the “cosmetics” of fawning poetry (or perhaps by literal cosmetics as well).
“She” here is synonymous with “woman”: “As any woman belied by a false comparison.”
Alternatively, the last line could be glossed as: the speaker’s perhaps not perfectly beautiful love proves despite her imperfections that the speaker has been making inaccurate and false comparisons. The line could thus be read as a meta-textual statement, a statement that contradicts or cancels everything that has been said before.
To help improve the meaning of these lyrics, visit "Sonnet 130" by William Shakespeare and leave a comment on the lyrics box