If you believe in Heaven, then you must believe in Hell. Scripture talks about both and you have to acknowledge the bad as well as the good. Hell is described as a place that "burns with fire and brimstone" (Rev. 21:8). And a place where God and Jesus are not.
And if you believe that God wants all of his people to go to Heaven, then you have to know that, by their choices and actions, some will not be in heaven but will go to Hell. "But the cowardly, unbelieving, abominable, murderers, sexually immoral, sorcerers, idolaters and all liars shall have their part in the lake which burns with fire and brimstone, which is the second death" (Rev. 21:8).
If you believe in life on this earth, then you must believe in life after death because scripture talks about both. In 1 John 5:13, the writer says he's written the things he did "that you may know that you have eternal life."
The question becomes, Where will you spend your eternal life — Heaven or Hell?