What is the authenticity of the Hadith that mentions a man heading towards Hellfire, then he turns around, and Allah asks him the reason for his turning, so he replies that he was hoping to enter Paradise, whereupon Allah orders him to be admitted into Paradise?

The aforementioned Hadith has a weak chain of transmission. The Hadith narrated by Muslim on the authority of Abdullah ibn Mas'ud, may Allah be pleased with him, suffices instead, as it describes the story of the last man to enter Paradise: He is brought out of the Fire, and Allah brings him close to three consecutive trees. Each time, he asks to be brought closer to the next tree until he reaches the gate of Paradise. He then hears the voices of its inhabitants and asks to enter it. Allah then grants him the world and its like along with it. The man says, "Are You mocking me, while You are the Lord of the worlds?" The Prophet, peace and blessings be upon him, laughed at the laughter of the Lord of the worlds, who said, "I am not mocking you, but I am capable of whatever I wish."