It means, 'Ah, why do you cry so little? Our desires are beyond measure.'

This beautiful couplet is a classic example of the intense, almost overwhelming nature of love. Mir Taqi Mir is telling the beloved not to cry so openly, because the passion (shauq) that resides in the lover's heart is far beyond any measure. It suggests that the depth of emotion is so profound that public displays of grief feel inadequate to express it. It's a poignant reminder that true passion often defies logic.