Does faith decrease if a person unintentionally commits a sin, and how can one restore their faith to be better than it was?

What occurred from the servant due to an unintentional mistake is pardoned, based on the Almighty's saying: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended." As for deliberate disobedience, it diminishes faith and necessitates sincere repentance for faith to return to its original state or become even better.