Compare the Good News taught by the Apostles and that by JWs by reading Galatians chapter 1:
"I was not called to be a missionary by any group or agency. My call is from Jesus Christ himself and from God the Father who raised him from the dead.3 May peace and blessing be yours from God the Father and from the Lord Jesus Christ. 4 He died for our sins just as God our Father planned, and rescued us from this evil world in which we live. 5 All glory to God through all the ages of eternity. Amen.
6 I am amazed that you are turning away so soon from God who, in his love and mercy, invited you to share the eternal life he gives through Christ; you are already following a different “way to heaven,” which really doesn’t go to heaven at all. 7 For there is no other way than the one we showed you; you are being fooled by those who twist and change the truth concerning Christ.
8 Let God’s curses fall on anyone, including myself, who preaches any other way to be saved than the one we told you about; yes, if an angel comes from heaven and preaches any other message(Good News), let him be forever cursed. 9 I will say it again: if anyone preaches any other gospel than the one you welcomed, let God’s curse fall upon him.
10 You can see that I am not trying to please you by sweet talk and flattery; no, I am trying to please God. If I were still trying to please men I could not be Christ’s servant.
11 Dear friends, I solemnly swear that the way to heaven that I preach is not based on some mere human whim or dream. 12 For my message comes from no less a person than Jesus Christ himself, who told me what to say. No one else has taught me."
Answer: The word gospel means “good news,” so the gospel of Christ is the good news of His coming to provide forgiveness of sins for all who will believe (Colossians 1:14;Romans 10:9). Since the beginning of time when the first man sinned, mankind has been under the condemnation of God (Romans 5:12). Because everyone breaks God’s perfect law by committing sin (Romans 3:23), everyone is guilty (Romans 5:18). The punishment for the crime of sin is physical death (Romans 6:23) and then an eternity spent in a place of eternal punishment (Revelation 20:15; Matthew 25:46). This eternal separation from God is also called the “second death” (Revelation 20:14–15).
The fact that all are guilty of sin and condemned to spend eternity in a place of torment is very bad news. But God, because of His love for the world, has made a way for man to be forgiven for their sins (John 3:16). He sent His Son, Jesus Christ, to take the sins of man on Himself through death on a cross (1 Peter 2:24). In placing our sin on Christ, God ensured that all who will believe in the name of Jesus will be forgiven (Acts 10:43).This is the gospel of Jesus Christ, the good news that God provided the way for man to be freed from the penalty of sin (John 14:6: Romans 6:23). But not all people will be saved from hell; only those who place their faith in Jesus will go to heaven when they die (Acts 4:12).http://www.gotquestions.org/gospel-of-Jesus-Christ.html
For the free gift of eternal salvation is now being offered to everyone; and along with this gift comes the realization that God wants us to turn from godless living and sinful pleasures and to live good, God-fearing lives day after day,
Titus 2:11-12 TLB