Say: Oh my servants who have wronged themselves (by committing sins), do not despair of the mercy of Allah! Verily, Allah forgives ALL sins. Verily, he is oft-forgiving, most merciful.
There is also a hadeeth Qudsi which mentions that every single sin, except for shirk, will be forgiven by Allah. All we have to do is be sincere in repentance.
Our lord is most forgiving, most merciful. Allah will even forgiven the one who has committed the most sins but has faith in Allah.
It is obligatory to not despair of Allah and have faith in Allah's mercy. Oh Allah, forgive us of our sins, those that we do in public and private, those that are major and minor, those that we commit knowingly and unknowingly, and those that we may end up committing in the remainder of our lifetime. Aameen.