Actualy, I believe I am right in Islam. And you believe your right. But what is the reality ? Why we follow many religions instead of one ?
Clearly, if both faiths are monotheistic it doesn't take a rocket scientist to realise that one is wrong.
However, I do not believe that anyone else on this website will agree that Islam is correct and Christianity is wrong.
It will be very difficult for us to alter your worldview given the number of lies about Jesus Christ and Christianity that are mentioned in the Quran.
If you really are interested in Christianity and the salvation that is in Jesus Christ we can talk, but I see no point in a philosophical discussion of the merits of Christianity versus Islam.