Well, then, Catholics believe wrong because that's not what Scripture teaches.
Sin cannot and does not separate us from God because once one is forgiven, having the record of debt that stood against us canceled, no sin remains to our account to separate us.
The poster is well taught in deceptions. Inherent in the poster’s supposition is the contradiction of ‘saved yet wickedness producing’. The problem stems from not having God’s Holy Spirit in the poster, so the false premise is fabricated to contradict the Bible Truth that once born from above the chld of God cannot commit wickedness and remain alive in Christ. To a mind steep in that cathalogic religion, the notion of gaining salvation, losing salvation, re-upping salvation via the priestly ministries to the confessor and remaining faithful to the rituals of that religion, the stamp of Catholic approval and working for reductions in purgatory, ... well, the notion of God’s unmerited Grace toward such an one just denies too much cathalogic ego need for pride in self. Catholics are big on ‘pride’ in their striving to obtain ... paradoxically, they deny that God’s Promise can assure them of salvation in the here and now. They refuse to be redeemed until they have merited it ...