Rey has died plenty of times to know what death is like for her -- a whole lot of nothing. It isn't that she's fearless in the face of death, though.

"Am hard to kill. Never claimed to be indomitable."

As for other healers...

"There is a doctor. Don't know anyone that can heal. Not like you can." Which, admittedly, is impressive even by Rey's standards. Her father's blood had healing properties to it due to cellular regeneration, but nothing like... magic.