What truth? Whose truth? Truth has nothing to do with Mortal Sin and the pathway to heaven. As for mercy, before "mercy" can be applied, the sinner must admit that he sinned and REPENT as his confessor directs him to do. Sometimes that repentance can be difficult for the winner as it should be. A murderer, for example, who confesses his sin, should not be surprised if the priest as part of the penance of the sinner demands that the murderer turn themself in to the police.