You can know for sure you are going to heaven:
First, realize God loves you…
Second, realize everyone is a sinner…
Romans 3:23 “For all have sinned, and come short of the glory of God;”
Third, realize sin has a price that must be paid…
Romans 6:23 “For the wages of sin is death…”
Revelation 21:8 “…and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.”
Fourth, Realize Jesus Christ died on the cross and rose again to pay your price…
Romans 5:8 “But God commendeth his love toward us, in that, while we were yet sinners, Christ died for us.”
Mark 16:6 “And he saith unto them, Be not affrighted: Ye seek Jesus of Nazareth, which was crucified: he is risen; he is not here…”