How do you know you are one of the chosen if you are Jehovah's Witnesses?

Answer 1

The witness of God's spirit convinces anointed Christians that they have heavenly prospects. "You received a spirit of adoption as sons," wrote Paul, "by which spirit we cry out: 'ABBA, Father!' The spirit itself bears witness with our spirit that we are God's children. If, then, we are children, we are also heirs: heirs indeed of God, but joint heirs with Christ, provided we suffer together that we may also be glorified together." (Romans 8:15-17) Under the holy spirit's influence, the spirit, or dominant attitude, of anointed ones impels them to apply to themselves what the Scriptures say about Jehovah's spiritual children. (1 John 3:2) God's spirit gives them a sense of sonship toward him and engenders within them a unique hope. (Galatians 4:6, 7) By means of his spirit, God has produced within them such a strong heavenly hope that they are willing to sacrifice all earthly attachments and prospects. (2 Corinthians 5:1-5, 8; 2 Peter 1:13, 14)

Answer 2

Quite simply, you don't. Just about EVERY religion claims they are "the chosen"; and their justification is tenuous at best.