When I was nineteen, I died...and remained dead for about two and a half minutes.

I have experienced life-threatening situations, spent time hiding in bomb shelters while air raid sirens blared outside and I have seen people die and get killed. And all I can say is that life doesn't weaken you, and neither does it strengthen you. It just provides the stressors and the challenges - it's totally up to you on how you react to those things.

Every saying I have ever heard is domain-specific, as in it requires detailed background and context to be understood and interpreted correctly. Life is too nuanced for it to be any different:)

I like this and I think it's true (the stoics would agree):
"indifference might even be considered to be a form of toughness"