Shakespeare’s speaker sets himself apart from poets who inflate their praise with gaudy, exaggerated comparisons. Those writers, he says, are stirred by a “painted beauty” and dress their verse with cosmic ornaments—sun, moon, sea gems, April flowers—piling up proud parallels that sound impressive but ring false. He refuses to join that game of overblown flattery.
Instead, he promises to write plainly and honestly, simply because his love is genuine. He admits his beloved is as fair as any real person, but not as dazzling as the stars fixed in the sky. There’s no need to pretend otherwise. The closing couplet adds a quiet, knowing shrug: let others who enjoy empty talk say more. He won’t praise with the ulterior motive to sell something. The mood feels gentle but firm, grounded in real affection rather than theatrical display. It’s a love that doesn’t need to shout.