Is repentance for lying and slandering another person by attributing to him the possession of pornographic films sufficient, or must he be informed of the truth, despite the fear of his reaction?

It is forbidden for you to clear yourself by attributing malicious acts to an absent person and accusing them of slander (buhtan). Allah, the Exalted, said: "And those who harm believing men and believing women for [something] other than what they have earned have certainly borne slander and a manifest sin." (Quran 33:58) And whoever says something about a believer that is not true about them, Allah will make them drink from the "radghat al-khabal" (mire of corruption). One who has fallen into this must repent to Allah and seek forgiveness from the one they slandered, because the rights of creation require seeking forgiveness for repentance, unless doing so would lead to greater harm. And defaming one's honor in this manner is akin to calumny, and repentance for it is by supplicating for the wronged person, not by informing them of what you did. You are not required to confess that you are the owner of those films to clear the slandered person; rather, it is sufficient to retract the attribution of those films to them and affirm that they are lies and fabrications. The summary is the obligation to repent to Allah from possessing or viewing those films, and from assaulting the honor of your Muslim brother without admitting your commission of forbidden acts.