Until Judgement day, a Muslim cannot know whether he has pleased Allah. Muhammad himelf said that he did not know what would happen to him at Judgement Day.
There is a well accepted Hadith where Muhammad is said to have been visiting a home where a Muslim man had died and the body was still there. A woman said to the dead, "May Allah's mercy be on you. I testify that Allah has honnoured you."
Muhammad said to the woman, "How do you know that Allah hounoured the man?"
She answered, "I do know, by Allah."
Muhammad replied: "As for him, death has come to him and I wish him all good from Allah. By Allah, though I am Allah's apostle , I neither know what will happen to me, no do you, " [The Correct Books of Bukhari, vol.9, bk.87, no. 145. Narrated by Kharija bin Zaid bin Thabit.]
Muhammad’s loyal follower Abu Bakr also spoke of fearing Allah’s judgment. He said, “If one of my feet were inside paradise, and the other one were still out, I would not yet trust the cunning of Allah” [Dr. Haykyl, Men Around the Messenger (Cairo, Egypt: Dar Al-Nahadah Publishers, 1972)]
Abu Bakr meant that his eternal fate was a mystery until both feet were inside paradise.
Abu Bakr was nicknamed the “crying man” because he would continually cry as he prayed. When asked about this one time his answer was, “Every time I start to pray I imagine Allah standing in front of me and the king of death behind me, the paradise to my right and hell to my left side, and I do not know what my God is going to do to me.” [Dr. Haykyl, Men Around the Messenger (Cairo, Egypt: Dar Al-Nahadah Publishers, 1972)]