People ask this all the time about Christianity, and the answer lies in the fact that the question is actually falsely premised. Specifically, Jesus isn’t merely a way to God—he is God. Exodus 3:14 states, “God said to Moses, ‘I AM WHO I AM. This is what you are to say to the Israelites: ‘I am has sent me to you.’’” “I AM” is one of God’s names, and Jesus used it to refer to himself in John 8:58, saying, “before Abraham was born, I am!” An open proclamation of his own deity. Also, John 1:14 refers to Jesus as “the Word,” and John 1:1 states that “the Word was God” (emphasis added).
Jesus isn’t a pathway to the destination, he is the destination.
Even if you reject the idea of Jesus’ deity, though, you still have to deal with another issue. He also said things like, “whoever rejects me rejects him who sent me” (Luke 10:16) and “whoever does not believe stands condemned already because they have not believed in the name of God’s one and only Son” (John 3:18). To believe the idea that Jesus is but one of multiple ways to God, you’d also have to believe that Jesus was a liar. I doubt, though, that a way to God would lie about himself or God. The only option you’re left with is to reject the accuracy of the Bible and that Jesus didn’t actually make any of the above statements. But why then would you believe Jesus is a way in the first place, if you don’t believe the Bible is accurate?
It’s easy to get hung up on a question like this and allow it to distract from not only the truth that Jesus is God, but also that the actual route he offers to himself is as open and broad as it could possibly be: “whoever believes in [Jesus] shall not perish but have eternal life” (John 3:16). You just believe in him – that he died so you could live – and he will take it (and you) from there. This path has no restrictions on who can walk it and requires you to do nothing (though after you choose it, you will naturally want to become more like Christ and live for him). God couldn’t have made it any simpler.
This is unique to Christianity. All other major religions teach that you must do certain things (which is their own version of the “one way” doctrine) to attain whatever their ultimate destination or state of being is (e.g., Heaven, Nirvana). Christianity, however, teaches that God has already done everything for you by sacrificing his perfect son on our behalf.
What better way could there be than that?