How to know Allah SWT has forgiven you?

So this is a great question because the honest answer is we do not know. Allah subhanahu wa ta'ala has hidden certain things from us. For example, Allah is hidden when we will die. Nobody knows 100% when we will die. Nobody knows whether any of our deeds have been accepted. Allah has hidden these things because he wants us to continue to turn to him and ask him for forgiveness. If we knew that Allah has forgiven all of our sins, it's very easy with the human nature which shaytan always whispering to us, we might not ask Allah for forgiveness as much as we did if we did not know whether Allah had accepted our forgiveness. So it's one of the things that Allah has hidden from us. Of course, we always think good of Allah. We always hope good in terms of Allah forgiving all of our sins. But nobody knows 100%. And the reason for this is because Allah wants to see if we will continue to strive and turn to him and do those good deeds and ask Allah for forgiveness.