I don’t think that’s just a Catholic belief. I think it’s a Christian believe.
John the Baptist talked about repentance. And Jesus said John was the greatest of all the prophets.
I take “repentance” to mean ask for forgiveness like you really mean it. Not just as an insurance policy, or to cover all your bases.
So if Hitler truly repented and accepted Christ…well, I’ll let folks decide about that for themselves. But I suppose you can guess my opinion from what I said above.
“I take “repentance” to mean ask for forgiveness like you really mean it”
True repentance is more than that, it actually means to change; to become a changed person having fully accepted Jesus as Christ and your savior and with your walk with Christ having become “born again” - a new person.