A woman has committed a grievous sin, like adultery, what are the ways before her for being forgiven?
There are many things that need to be clarified in this issue. Firstly, there are 3 conditions for tawbah (repentance) to be accepted.
1. You should be ashamed and regret about the sin that you have committed. One should feel bad from the depth of his heart for stepping on the boundaries set by Allah. Your heart should prick you and make you grieve. This is sign of a good faith. If you do not feel ashamed of your sins nor regret for committing it then Tawbah (repentance) is not done sincerely.
Abdullah bin Masood (Allah be pleased with him) says, “For a Believer, even a small sin which may be the size of a fly or a mosquito, should appear like a mountain before him.” This is called the real fear of Allah.
2. Discard the sin for ever.
3. Make a firm resolution of never repeating the same sin ever.
If you repent with the three above mentioned conditions, then In sha Allah your repentance will surely by accepted by Allah. There is no special method allotted to repent except that one has to raise his or her hands in Dua and weep for having committed that sin and plead for the Mercy of Allah
Secondly, always keep in mind that if you have committed such sin then see to it that you keep it confidentially with Allah and do not share it with people. Keep it covered from the people as the Prophet (peace be upon him) himself suggested, “All the sinners of my Ummah will be forgiven except those who keep on sharing it with others.” Always keep your sins covered. Now onwards, see to it that you do not un-cover your sins so that Allah will forgive you.
Keep on repenting whenever you recall your sin.
Plead to Allah that you were caused to be slipped by Shatyan and you would see to it that you will not repeat it again.