Du'a for forgiveness: My Lord! Lo! in Thee do I seek refuge

رَبِّ إِنِّيٓ أَعُوذُ بِكَ أَنۡ أَسۡـَٔلَكَ مَا لَيۡسَ لِي بِهِۦ عِلۡمࣱۖ وَإِلَّا تَغۡفِرۡ لِي وَتَرۡحَمۡنِيٓ أَكُن مِّنَ ٱلۡخَٰسِرِينَ

Rabbi Inneee A-o’od’u Bika An As-alaka Maa Laysa Lee Bihee I’lm Wa Illaa Taghfirlee Wa Tarh’amneee Akum Minal Khaasireen

My Lord! Lo! in Thee do I seek refuge (from the sin) that I should ask of Thee that whereof I have no knowledge. Unless Thou forgive me and have mercy on me I shall be among the lost

Qur'an 11:47 (Hud)