Student or Learner
Is there an expression or word to describe the willing or desire that one have to overcome a difficulty or a challenge?
It's going to be tough but I have a lot of ... and everything is going to be fine at the end.
Determination? Resolve? Willingness?
"Determination" or "resolve" are better than willingness, which means simply that you are agreeable to doing it. I'd pick "resolve".
You could also say "will" or "intent", but then I suggest "my will/intent is strong".
Another way to express the same thought is "I am firm".