Do you believe that non-Muslims will go to heaven without converting to Islam.. ?

Who will go to heaven and who will go to hell is strictly the domain of God. No one knows. Even Muslims cannot claim that they will go to heaven. God will decide it on the Day of Judgment. The Quran says: "It will be a Day when no human being shall be of the least avail to any other human being, God [alone] will hold command on that Day." (82:19)