You can't just say "I believe in Jesus now" and go to heaven. You need a repentant spirit. God doesn't want hypocrites, or people who think they can just ask for forgiveness every time they do something wrong, without making an actual attempt to stop sinning. That isn't genuine belief, that's just posturing.
The perfect passages to describe this in the bible are James 2:14-19
What good is it, my brothers and sisters, if someone claims to have faith but has no deeds? Can such faith save them? Suppose a brother or a sister is without clothes and daily food. If one of you says to them, “Go in peace; keep warm and well fed,” but does nothing about their physical needs, what good is it? In the same way, faith by itself, if it is not accompanied by action, is dead. But someone will say, “You have faith; I have deeds.” Show me your faith without deeds, and I will show you my faith by my deeds. You believe that there is one God. Good! Even the demons believe that —and shudder.
powism