Do you ask yourself this question? Am I sincere? Do you doubt you are sincere? How do you know if you are sincere?

How can we deal with self-doubt regarding our intentions? The Prophet (pbuh) taught us this dua!

اللَّهُمَّ إِنِّي أَعُوذُ بِكَ أَنْ أُشْرِكَ بِكَ وَأَنَا أَعْلَمُ ، وَأَسْتَغْفِرُكَ لِمَا لَا أَعْلَمُ

O Allah, I seek refuge with You lest I should commit shirk with You knowingly and I seek Your forgiveness for what I do unknowingly.