How can I seek forgiveness, and will my repentance be accepted if I commit an act that I know is forbidden—such as holding a wedding celebration?

Wedding celebrations are not permissible if they include forbidden acts such as intermingling (between sexes) or musical instruments. Whoever commits such acts must seek Allah’s forgiveness and repent. Seeking forgiveness (Istighfar) is asking Allah for His pardon, and it can be achieved through any wording that signifies this, though the preferred way is through the narrated (prescribed) formulas. The acceptance of Istighfar and repentance is a matter of the Unseen, but there are signs that indicate acceptance.