أَسْتَغْفِرُ اللَّهَ الَّذِي لَا إِلَٰهَ إِلَّا هُوَ الْحَيُّ الْقَيُّومُ وَأَتُوبُ إِلَيْهِ
Astaghfirullaha-lladhi la ilaha illa huwal-Hayyul-Qayyumu wa atubu ilayh
I seek forgiveness from Allah, there is no deity but He, the Ever-Living, the Sustainer of existence, and I repent to Him.
Recite for deep repentance and forgiveness of major sins
The Prophet (PBUH) said: 'Whoever says this, his sins will be forgiven even if they are as much as the foam of the sea.'