Taking your example of Christ’s resurrection, we can see that it describes an event. So we can understand that it is either a real event or an unreal event.
Either the Resurrection happened, or it did not.
If I believe it really occurred in history but you believe it didn’t, only one of us can be right. We cannot both believe the truth while holding opposite views.
This explains how there cannot be multiple truths; reality provides exclusively for the contrary, that there is only one truth.
True, there cannot be multiple occurences of the same event. We’re not talking about physical events in this conversation though, are we? We’re talking about our souls, our beliefs, our moral truths if you will, right?