It is said that if evil people leave their evil ways and walk on the right path God will take over. Yes, does take over and help them rise to rise higher, but this does not mean He forgives them and welcomes them to heaven as soon as the evil people say they want to be on the good side.
Definitely not, you have to pay for your sins, no matter what. But if you have the genuine desire to change, God will definitely help you. That will only happen when you truly repent for your bad deeds and God is sure that you will not go back to your old ways. Only then will God help you rise up sooner. God will guide you and teach you to pay off your karma in a good manner.
You should by no means believe that if you are evil at one moment and then think of God and worship him the next, you will reach heaven. It is silly to confess to a priest and think that God has Forgiven you. Your inner motive – a genuine desire to change for better – is the only thing that matters.