How do you make me love you more precisely because I have reason to hate you—and if my love was raised by your unworthiness, shouldn't my worthiness deserve yours?
Lines 5–8 invert value: her 'refuse' (waste, worthlessness) becomes precious; her 'worst all best exceeds.' This is not love as traditionally understood but a kind of spiritual alchemy where defect becomes virtue. The speaker has reversed the entire moral economy—he loves her *because* she is unworthy, not *despite* it. This is psychologically keen: he has justified his degradation by making her unworthiness the locus of attraction.
The couplet's argument—that he deserves reciprocation because he loved the unworthy—presumes love creates obligation. Yet the entire sequence has shown the beloved feels no such debt. This is the speaker's final rationalization: if he cannot win her, he can at least claim moral superiority through his sacrifice. It is hollow but poignant.
Like someone saying, 'I loved you despite every reason not to, which should prove I'm worthy of being loved by you'—a last-ditch attempt to convert suffering into entitlement.