The title makes the reader expect the sonnet is about a coy woman and a man writing, who is caught by her love. The sonnet starts with an if-clause, because the man is aware they have not much space and time for their love; in fact a human being will never live forever. So in his opinion and maybe in most of men's too, coyness is a crime. However he is suffering for what is happening, because he is totally felt in love with her, as she made him a spell, and that is why he uses a high register. He tries to make her understand his opinion about her coyness, by using some religious metaphors, to underline the importance of the theme.  There is plenty of rhymes at the end of the verses and the reader listens often the sound "ai", that remember the "voice" of someone, who is suffering.