Psalm 83:18.....reason Jehovah's Witnesses preach worldwide: to help people come to a knowledge of Jehovah, our Creator, His purpose for mankind, what He has done in the past, what He is doing now and what He is going to do in the future. He has advised us of all this through His word, the Bible.
Only a select few go to heaven. Revelation 14:1-3 gives them a number 144,000, bought from the earth to rule with Christ in heaven. They will rule over righteous mankind who will live forever on the earth.
Jehovah's Witnesses love Jehovah and Jesus Christ in their hearts.