"I'm just thankful there is no Heaven and there is no Hell." Dean Christiansen.
You can only “believe” that there is no Heaven and no Hell. You cannot "know" because you have no trustworthy authority from which you can derive knowledge. Proof of their existence, however, depends on God's faithfulness to fulfill His promise to manifest Himself to all who call upon Him. This comes through repentance and faith in Jesus. Millions have found Him to be utterly faithful, and we can only tell you what we know to be true.
It is then up to you to have an open mind and seek the truth for yourself. We are talking about where you will spend eternity. This is no game. Please check out www.needGod.com