Surah Yusuf — Ayah 27 (12:27)
وَإِن كَانَ قَمِيصُهُۥ قُدَّ مِن دُبُرٖ فَكَذَبَتۡ وَهُوَ مِنَ ٱلصَّٰدِقِينَ ٢٧
English translation (Saheeh International)
But if his shirt is torn from the back, then she has lied, and he is of the truthful."
Brief commentary
But if his shirt is torn from behind, then that is an indication that he is truthful, because she was trying to seduce him whilst he was running away; and she will be lying.