Answered by Sayyidi al-Ḥabīb `Umar bin Hafīẓ (may Allāh preserve him and benefit us by him).

How does someone remove hardness from their heart?

By seeking forgiveness often and having a heart that is broken before Allāh in the depths of the night and reciting the Qur’ān with reflection, and remembering that our ultimate end is to Allāh.