In order for forgiveness to be accepted, these conditions should be met:
(1) The crime is committed out of ignorance, not with the intention that, "Let us go ahead and commit this crime as Allah is forgiving, so He will forgive us.";
(2) Quickly turn into shame and repentance after committing a crime out of ignorance;
(3) After asking for forgiveness, make a promise or pledge to "mend his ways", and to stick to his promise. Let us examine verses of Quran.
"...if any of you did evil in ignorance, and thereafter repented and amended (your conduct), lo! Allah is Oft-Forgiving, Most Merciful." (6:54)
"Forgiveness is only incumbent on Allah towards those who do evil out of ignorance and then turn quickly (in repentance) to Allah. Toward them will Allah turn in mercy; for Allah is full of knowledge and wisdom." (4:17)
"Forgiveness is not for those who do ill until death faces one of them, who then says, 'Lo! I repent now, nor for those who die as disbelievers, for such we have prepared a painful doom.'" (4:18)
You have to apologise, if you want Allah to forgive you.
I hope this helps, (insh'Allah)