Question: How do we know if one is bound for the hells in the next life?
Answer: When one is clearly unrepentant, by continually doing great evil, with breaking of the precepts, by killing, stealing, sexual misconduct and/or unwholesome speech (with attachment, aversion and delusion), which harms other(s) much, be it physically or mentally, one is clearly bound for the hells. The continual doing of evil expresses the very lack of repentance, thus increasingly deserving the hells karmically.
Question: How easy is it to fall into the hells?
Answer: It is not difficult at all. One of the easiest ways to do great evil is to have unchecked speech online. For example, by posting slanderous false speech (妄语), perhaps with a fake identity, with double-tongued speech (两舌) and/or harsh speech (恶口). The more it is seen, the more evil karma there will be, with ill effects that are difficult to undo. Words heard or read is like water poured away, almost irretrievable. Anonymous groundless poison pen letters are likewise thus.
Question: What if that ‘said’ was believed to be true?
Answer: One should have checked with multiple sound sources, including the person(s) in question in advance, to be truly objective. Obviously, if one simply rants on, based on delusional speculations only, one should already know oneself to highly possibly have false speech — what more if others already repeatedly tried to sincerely clarify to present the truth, with it repeatedly ignored.
Question: Can one simply repent before life ends, to escape the hells?
Answer: If as mentioned, there is continual doing of evil, one is clearly unrepentant already. The chances of such a habitually evil person will suddenly be able to have sincere and thus effective repentance on the brink of death (which can arrive at any time due to life being unpredictable) are close to none. The only way to prove to oneself that one can be repentant is to be so now, as expressed by no longer doing evil, with open apologies to make up for the harms done. If not, before falling into the hells, there is also the possibility of evil karma ripening in this life to bring great shame upon oneself soon, when one’s identity with one’s evil deeds are disclosed. This applies to all individuals and their passively supportive partner(s) in crime.