There is no effect without cause. You were born here and exist for a reason and until that reason will disappear you will continue to be born and exist. When that reason will disappear you will not exist anymore and will enter nirvana. If you think that you were born here and exist without a reason then that implies that you could be born and exist in hell for 92834234 trillions of years without a reason or if hell seems too far fetched for you consider africa or having major depression etc.
Having thus accepting that we will continue to be born and exist in the future because we have not destroyed the cause for been born and existing here right now that implies that we could be born and exist in an innumerable states of existence, both good and bad, with access to dhamma or without. These innumerable states of existence were classified by buddhist in 6 realms but not all beings in a realm are the same, look how big the variance of happiness/sadness can be here on earth from one being to another. The extent to how bad or how good a state of existence can be is hard for us to imagine but we can resonably assume that it can be worse or better than here on earth and seen how bad some lifes can be here on earth is enough to scare the ... out of anybody.
If hell seems to far fetched consider a place where your dopamine and serotonine levels are lower than in a person having major depression, that won't seem so far fetched as beings freezing with their organs out of their bodies.
Also consider that any bad deed has a limited effect so been sent to hell for eternity would mean an infinite punishment for a finite cause. That implies that been sent to an eternal heaven or human realm etc. is also impossible.
The idea scares me very much too and budhism is way more pessimistic (and realistic) than the other religions but ignoring the posibility of been born and existing in "hell" won't make it disappear. Becoming a sotopana will
PS: Our happiness is given ultimatly by the levels of some substances in our brain so hell could be a place where beings have low levels of those substances in their brains. For the same reason we have this complex external environment that rises and lowers those substances here on earth (a nice car, a wife etc.) we could have a complex environment that rises and lowers those substances in other forms of existence too, for example lying in freezing tempreture with your organs out of your body. We are not balls of light that are happy/sad here on earth so a complex environment that makes us be happy/sad should also exist in other realms of existence.