How does a Muslim know if a difficult life is a trial from Allah or a manifestation of His wrath?

Allah tests His servants as He wills. The Almighty said: "And We test you with evil and with good as a trial," and He said: "And We will surely test you with something of fear and hunger." Tribulation can be for the expiation of sins, as in the Hadith: "No worry or sorrow afflicts a Muslim… except that Allah expiates some of his sins by it," and it can be for the elevation of ranks, as is the case with the tribulations of the Prophets. It can also be to distinguish believers from hypocrites. The Almighty said: "And We have certainly tried those before them, and Allah will surely know those who are truthful and will surely know the liars." It can also be a punishment for a believer for sins he has committed. The Muslim understands the reason for the tribulation: it may be due to committing a sin, or negligence in a matter, or for the elevation of ranks. As for those steeped in disobedience without repentance, Allah may hasten their punishment in this world.