I would guarantee you that I am going to heaven for I believe in Jesus and the Salvation he gave to me and every person on this earth when he died on the Cross. I can tell you this for in the Bible it says

"For God so loved the world that He gave His One and only Son that whoever believes in Him shall NOT perish but have Eternal life." John 3:16

Thats where my faith is and thats why i know im going to be in Heaven with the Lord when I die