Just like anyone else, I have done things I'm not proud of, to be more specific things like commit adultery (zina), disown my parents, drugs and turning my back on people who needed help. I know all of it is haram, yet throughout all of this I always believed if not anything else, that there is no god but Allah and Mohammad(as) is the messenger and servant of allah. I have asked allah(swt) to forgive me on multiple occasions, but in all truth I don't think I have the capability to enter jannah. There are some things I have done in my life, that I can't undo because it already been done and it's just killing me inside. Will just my BELIEF be sufficient enough for the almighty and merciful Allah(swt), since for now I am incapable in doing the right things in my life and correcting myself. All in can do is repent.
Indeed, they who have believed and done righteous deeds - those are the best of creatures. Their reward with Allah will be gardens of perpetual residence beneath which rivers flow, wherein they will abide forever, Allah being pleased with them and they with Him. That is for whoever has feared his Lord. (Qur'an 98:7-8)
There is an 'and' present in up there, not an 'or'.
But the Jews and the Christians say, "We are the children of Allah and His beloved." Say, "Then why does He punish you for your sins?" Rather, you are human beings from among those He has created. He forgives whom He wills, and He punishes whom He wills. And to Allah belongs the dominion of the heavens and the earth and whatever is between them, and to Him is the [final] destination. (Qur'an 5:18)
So, even for a believer, (I mean who just believed), he has to ask forgiveness with true repentance from Allah, at least before he breathes his last breath.
Verily, Allah is Oft Forgiving, Most Merciful.
But, if he was just a believer and failed to ask forgiveness from Allah, then
He admits whom He wills into His mercy; but the wrongdoers - He has prepared for them a painful punishment. (Qur'an 76:31)
Does it say, he will punish the disbelievers? No, clearly it says the 'wrong doers'.
So, we cannot take a chance. Ryt?
May the creator guide us all.