What does they believe that a person's true potential is unknown (and unknowable); that it's impossible to foresee what can be accomplished with years of passion, toil, and training mean?

These people believe that a person's true potential is unknown (and unknowable), that it's impossible to foresee what can be accomplished with years of passion, toil, and training.-People with fixed mindset believe love is ideal, instant, perfect, and characterized by perpetual compatibility. Like it was meant to be. Like "living happily ever after."  

-Unfortunately, people with fixed mindset believe relationship failures and rejection say something about them

Growth Relationship Mindset

-People with growth mindset believe that they, their partner, and their relationship can grow and develop  

-Importantly, growth mindset doesn't mean there isn't a "soul mate" out there for you. It does mean that even with that destined person you will continue to grow and get better!

Explanation:

- "he is a very real person and his intent isn't to influence us vonnegut addresses this towards the end of the letter when he says, if we choose to curse, that is by our own individual means."