There are many people who sincerely believe in a different religion. However, sincerity does not make something right or beneficial. People can be sincerely wrong. Truth is what matters, and it is not possible for every religion to be true because they contradict each other. Christianity has some distinctive features which are not compatible with other religions. Other religions say you must do certain things in order to be right with God. Christianity says Jesus has done it all, by dying to take the punishment that we deserved so that we can receive God’s forgiveness.
If Jesus is the Son of God then he alone can speak authoritatively about religion and the way to God. Indeed, he himself said: "I am the way and the truth and the life. No one comes to the Father except through me." We cannot therefore come to an answer to this question until we have properly considered him.(John 14:1-16, Romans 9:30-10:15