Getting to the heart of this question can be problematic because of various other aspects that become attached to it. For example, discussion can quickly become quite emotional with claims of prejudice and bigotry levelled at Christians for claiming that Jesus is the only way to God. The question can also unhelpfully become confused with sincerity. However, we must remember that it is possible to be sincerely wrong. I have been on a number of occasions!
People can, of course, choose to believe what they wish but we have no right to redefine Christianity in our own terms. When Jesus himself claims that he is the only way (see John 14:6), Christians have no other option but to believe and state the same if they follow him. If Christians sound exclusive it is because their leader was exclusive in the first place.
It is not logically possible for all religions to be right because they contradict each other on several key points. For example, for the Buddhist the way to enlightenment is to follow Buddha’s ‘eight-fold path’. For Muslims, only strict obedience to Muhammad’s teaching as found in the Koran will bring Allah’s favour. Hinduism teaches that there are millions of different gods in the universe. They could, of course, all be wrong but they cannot all be right.
One helpful way to remember the differences between Christianity and other religions is that all other religions are about ‘doing’ while Christianity is about what has already been ‘done’ for us. It is about a relationship between people and God that is made possible through Jesus and his death and resurrection. You might like to read the Bible for yourself and think through some of these key differences between Christianity and other religions.