Are there any Christians who don't believe in hell and who don't believe they are sinners?

I can't answer to others

But Jehovah's Witnesses do believe in 'hell', just not the false teaching that hell is a place of torment that never comes to an end.

Jehovah's Witnesses understand, ALL of mankind fall short of the glory of God, and therefore, All are sinners, with the exception of Jesus.

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Maybe some who think they are Christians. However both of those truths are central to genuine Christianity.

God says about Adam. "for dust you are and to dust you will become." The wages of sin is death. Only the righteous will have a resurrection to live again. So when you die you are just gone. Why has God waited so long? To get enough righteous people to fill the earth

In order to become a Christian, people must first understand they are lost sinners who need a Savior. Only Jesus Christ is the Savior. Once they grasp that the Lord Jesus Christ died on the cross to pay for their sins and rose again and trust in Him alone for the free gift of eternal life, they are saved forever. They are not saved until they reach that point.

Because we have all sinned against a perfectly holy and righteous God, we all deserve eternal separation from God in hell (Rom. 6:23). However, God loves us so much that He sent His only Son Jesus to die on the cross as our Substitute so we don't have to go to hell. Christ died for our sins, was buried, and rose from the grave three days later (1 Cor. 15:3-4). He gives eternal life freely to anyone who simply believes in Him for it. No one can be saved by doing good works. Salvation is by grace alone through faith alone in Christ alone (Eph. 2:8-9).

"Verily, verily, I say unto you, He that believeth on me hath everlasting life" (John 6:47).

What fake newspaper did you read this article in?

Put the link of the newspaper, otherwise I have to say that you are a fake person, both in Virtual and in Real life?

TRUE Christians have always believed according to the word of God that there is Heaven, and hell, heaven is given to its faithful believers, while hell is given to all the Evil ones, including their sins!

Another thing, if a Christian has sinned, he will ask God for forgiveness, and will be forgiven, with God's help he will no longer sin, because God is Love!

Is the bright yellow rose a symbol of jealousy?

Do you believe the Holy Ghost would "dwell" (Romans 8:9) in an unclean "temple" (I Corinthians 6:9)?

"Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?

If any man defile the temple of God, him shall God destroy; for the temple of God is holy, which temple ye are.

Let no man deceive himself. If any man among you seemeth to be wise in this world, let him become a fool, that he may be wise" (I Corinthians 3:16-18)!@.

Anyone who believes they are a sinner "...have not resisted unto blood, striving against sin" (Hebrews 12:4)!

"For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost [Holy Spirit baptism; Acts 1:5],

 And have tasted the good word of God, and the POWERS of the world to come [Received after Holy Spirit baptism; Acts 1:8], 

If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame" (Hebrews 6:4-6).

"For if we sin willfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,

But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries" (Hebrews 10:26-27)!@.

"But the cowardly, the unbelieving, the vile, the murderers, the sexually immoral, those who practice magic arts, the idolaters and all liars—they will be consigned to the fiery lake of burning sulfur. This is the second death.” (Revelation 21:8)!

"This:, it will be said, "Is the Fire,- which ye were wont to deny! "Is this then a fake, or is it ye that do not see? (Quran)

Sinners and hell are two things that go together hand in hand. But as GOD said, the best sinners are the ones who know they are committing sins and then ask for pardon and forgiveness from GOD and feel sorry to what they have done ,GOD always listen  to their call and forgive them , since GOD is all forgiving most merciful. For the worse sinners are the ones who commit sins and never realize that they commit sins , then still going on in committing sins till their last breath, so these sinners never have chance to repent for their sins to GOD , then die with their sins hand in hand going to hell with satan. As you know the grave sin against GOD is to ascribe partner to HIM , by saying that Jesus is the son of GOD and further more they say that, in saying Jesus as the son of GOD is not ascribing partner to GOD.

I must admit ,your question is deep,

No. Anyone believing those things would not be a Christian.

If there are, they aren't Christians.