If a Muslim were to read the Quran with the purpose to find out how to avoid being sent to Hell, they would find out, were they honest with themselves, that even if they dedicate their entire life and will to Islam, they are still 100% certain to be doomed.
To demonstrate this, this article compiles a comprehensive list of everything that will get you sent to Hell in Islam, according to the Quran.
Hell is mentioned on pretty much every page of the Quran, and every single reference that is included here explicitly mentions Hell, hellfire, burning, or damnation. None of them are ambiguous or would require my speculation.
Note that "disbelieving", by far the most common transgression attributed to those bound for Hell, includes not obeying everything that Muhammad has ever decided (Surah 4:65, 24:47), and not loving Muhammad more than any other human being on the planet (Sahih al-Bukhari 14-15). Muhammad's concept of "belief" is pretty much performance-based, with no allowance for the concept of hypocrisy - if you don't live in accordance with your faith, then you don't truly have faith at all (now where have I heard that before?).
Without further ado, here are each of the things that will get you sent to the fires of Hell in Islam. Note especially that any one of these will get you sent to Hell. You need not do all of them to wind up burning, just one:
So, there we have it. If you aren't a Muslim, you're definitely going to Hell, and even if you are a Muslim, you are still definitely going to Hell, if you are honest with yourself, and have a proper view of the holiness of a perfect God.
If we take even moderate definitions of these stipulations, I could convict every last person on earth under one or more of them - and I don't have perfect knowledge like Allah ostensibly does, neither does he indicate anywhere that he would take a "moderate" definition of any of these things. If he did, he would be accepting less than perfection, which is moral perversion.
There can be no assurance of Salvation from Hell in Islam, because Muhammad defines "belief" as "obedience", which results in condemnation by, at the very least, one of the dozens of verses that make it clear that disbelievers will go to Hell, or certainly by one of the other stipulations, even if you are a Muslim.
The idea that faith means "works" or "obedience" is not novel to Islam - it is the same thing that is taught by every false Christian group, and it is unbiblical (Romans 4:5, Ephesians 2:8-9, Romans 11:6, Titus 3:5). Faith/belief in regard to the Gospel in Biblical Christianity simply means "to trust", specifically, to trust Jesus Christ to save you - this is not so in Islam.
If you don't perform well enough, which you don't and won't - no one can meet the ridiculous standard laid out in the Quran - you will go to Hell. You don't have to transgress all of the things in this list, you only have to come short once. They each carry the penalty of hellfire on their own according to the Quran.
This, combined with the conspicuous predestination taught in Islam, is why even Muhammad had no assurance of Salvation. The religion of Islam truly puts Muslims in a horrific, restless, anxious situation, to which few other false religions can even compare.
The good and bad news for Muslims is that the standard in the Bible is actually higher than that of the Quran - utter perfection from birth until death is required, as you will be judged in righteousness by Jesus Christ, who never sinned (Acts 17:31). If you have no payment for sin, you will fail to meet that standard, regardless of how well you did, relatively speaking, to other sinners (Romans 3:10-12, 3:23).
The good news is, God offers you a payment for your sins, and justification before Himself, based on simple faith in Jesus Christ, who paid for the sins of all mankind by His death and resurrection:
Romans 4:4-8
4 Now to him that worketh is the reward not reckoned of grace, but of debt.
5 But to him that worketh not, but believeth on him that justifieth the ungodly, his faith is counted for righteousness.
6 Even as David also describeth the blessedness of the man, unto whom God imputeth righteousness without works,
7 Saying, Blessed are they whose iniquities are forgiven, and whose sins are covered.
8 Blessed is the man to whom the Lord will not impute sin.
It would be an unimaginable error to reject that offer of payment, and try to make it to Heaven based on your own righteousness, which will not happen, regardless of whether Muhammad's fake standard, or the Bible's real standard, is used (Romans 10:3-4).