…the mercy of God has no limits if one turns to him with a sincere and contrite heart;
Or: sincere repentance always leads to forgiveness.
…the question for one who doesn’t believe in God lies in obeying one’s conscience.
Or: if someone does not believe in God, does God forgive them their sins? Well, this forgiveness is dependent on their conscience. Why? Well…
Sin, also for those who don’t have faith, exists when one goes against one’s conscience.
If a person is disobedient to their conscience, regardless of whether or not they have faith, then they sin. It is possible to not have faith and to go against one’s conscience in so doing.
To listen to and to obey it means, in fact, to decide in face of what is perceived as good or evil. And on this decision pivots the goodness or malice of our action.
Our actions are good or evil, for us subjectively, based on the decisions we make as informed by our conscience.
Based on the above: does a murderer follow his conscience in killing, or is he deliberately choosing against his conscience? How do we know? Well, we don’t.
Likewise, is the unbeliever refusing to believe in God as a result of a suppression of their conscience? How do we know? As above, we do not know.
The headline should be disregarded: the Holy Father has not stated whether or not it is even possible to have a conscience that can lead a person to unbelief in God. Furthermore, Pope Francis has not defined, in this letter, what a conscience even is.
I would state, also, that I wonder whether our Holy Father wasn’t speaking directly to Dr. Scarfali’s soul in his comments. You need to examine yourself, and really determine whether or not your own conscience is telling you that disbelieving in God is wrong, because you too will be judged.