 How can we know if we are forgiven? If you fulfill the conditions of toba, of repentance, if you have remorse for it, that you stop doing it while you're doing it, you intend to never do it again. Having said that, one of the greatest signs is, is that Allah ta'ala moves you out of that state and he takes you into a better state. This potentially could be one of the signs that your repentance is accepted. And then after that, that you're in a state of purity and you don't ever think about that stuff again. If that you still think about it, you should remember the pain associated with that sin to cause you and protect you from going back in a second time.