Put it at the end of an edit, just after the unfair reveal, as the closing reaction. Follow it with the Ba Dum Tss Drum Sting for a dry punch, or lead into it with the Evil Laugh Sound Effect when the misfortune is deliberately comic.
About this sound
This is a short Portuguese voice clip speaking the line 'que mundo é esse tão cruel', roughly 'what a cruel world this is', in one brief, clear burst lasting under four seconds. It carries disbelief and frustrated drama, turning a small unfair setback into something theatrically oversized, so listeners feel the exaggeration even without understanding every word.