If someone marries the person he has committed fornication with, will the sins of that fornication be forgiven?

If a man has a premarital relationship with a woman he is going to marry, that is, if they commit fornication and if they get married later, will the sins of the fornication or relationships before marriage be forgiven? Or will their relationship continue as a sin of fornication?

Dear Brother / Sister,

Firstly, the approach “Allah will forgive anyway” while committing a sin is wrong. It will be deadly wrong to plan a sin with that approach. Allah knows what is in the hearts. It is necessary to act sincerely toward Him. However, a person who commits a sin by obeying his soul can expect to be forgiven by Allah if he is really regretful.

It is not enough for a person who has an illegitimate relationship with a person from the opposite gender to marry him/her for his sin to be forgiven. It is also necessary to repent, and to ask for forgiveness from the person if violation of rights is in question. A sin is committed once and it is recorded as a sin once. If that sin is not forgiven, it is recorded as a sin.  

If a person repents and marries the person with whom he committed fornication, his relationship with his wife is not regarded as fornication after that.

Questions on Islam