The poet attempts to defend his beloved against the slanderous accusations of the previous sonnet. Some casuistry is involved, as usually happens in these cases, but the conclusion is reasonably serene, and the power of the youth to rule over others by his beauty and perfection is acknowledged. If there were no blemishes, real or imaginary, attached to him, then surely he would be the wonder of the world and whole kingdoms would fall at his feet. That thou art blamed shall not be thy defect, 1. The ornament of beauty is suspect, 3.
Suspicion always accompanies beauty, such that it seems to be a natural adornment of it.
Describing suspicion as an ornament of beauty is rather odd, since ornamentation itself is supposed to beautify the object. It may be that the title is applied ironically, or there may be a suggestion that all ornaments are false and should be the object of suspicion. A crow that flies in heaven's sweetest air. A crow was considered to be a bird of evil omen, mostly because of its blackness. So thou be good, slander doth but approve 5.