God describes His will in great detail in the Bible. So the first thing to do is to study the Bible to determine if what has happened is consistent with God's character. In other words, was it something that God would deliberately cause to happen? For example, God would not cause a person to stumble into sin. That would be contrary to His character. God is for us, not against us. Perhaps if you would describe what has happened, we could help you to determine if it was God's will or just a coincidence.