Using the Latin root mort meaning death and the prefix im meaning not, the meaning of immortality as used in this sentence from the passage most likely means

immortality means the ability to live forever or have eternal life. If you break it down by root and prefix - it would be (im) not (mort) dead or not dead.

Answer and explanation:

From the root "mort" meaning death, we have the adjective mortal, which means someone who is subject to death or something that is fatal (causes death).

By adding the prefix "im", meaning not, to mortal, we have the adjective "immortal". If mortal is someone who is subject to death, an immortal person is someone who isn't, who cannot die, whose existence cannot be finished.

Immortality is the condition or quality of being immortal. If you have immortality, you have an unending existence, eternal life.