Is it permissible for a Muslim to ask his Lord to show him a sign to reassure his heart, similar to what happened with our master Abraham, and for this sign to be the cause of his conviction that he is a believer?

Ibrahim, peace be upon him, asked to see how Allah brings the dead back to life, so that he might witness it firsthand, thus reaching the certainty of sight (ayn al-yaqin) after the certainty of knowledge (ilm al-yaqin), as stated by Al-Sadi and Ibn Ashur. This indicates that faith increases and decreases, and that it is permissible to ask Allah for a proof that increases certainty and faith, as the boy did in the story of the People of the Ditch, and as Ibn Umar did when he prayed to Allah to show him a dream that the Prophet, peace and blessings be upon him, would interpret.