Did Jesus Christ really rise from the dead?
If the answer is no, then Christianity is proven to be false. As the Apostle Paul puts it, if Jesus did not rise from the dead, then Christians are to be pitied more than any other, as our faith is useless, futile, without foundation, worthless.
However, if the answer is yes, then there is good reason to believe in the truthfulness of Christianity. The question then becomes, how do we know whether Jesus really did rise from the dead?