it's 100% possible to prove true or false, you just can't tell anyone. you simply have to die and then you'll know.
some people have died, and claim it is real, but evidence is mixed of course. Some muslims get revived and say Islam is real, some die and see just a bright light, some die and say they see hell, etc.
Dead to sin, alive in christ, a new creation.
The old man left behind, the new man walking with the lord.
You only mention the physical death in your example, but spiritually the complete ending of your old, independent life so that Christ can live His life through you. You cannot experience the resurrection of the new self without first experiencing the execution of the old self.