What do you mean, jump over the mountains and cross the sea and be fearless for the rest of your life?

This sentence means that when we jump up bravely and throw ourselves into the challenges and adventures in life, we can find our inner strength and be fearless in the future life.

"Jumping over the mountains and crossing the sea" can be understood as facing all kinds of challenges and adventures in life. This kind of jumping courage can inspire our inner motivation and confidence, and let us dare to pursue our dreams and goals.

"I will spend the rest of my life fearless" means that after such brave actions, we will become stronger and more confident, so that we will be fearless in our later life. No matter what difficulties and challenges we encounter, we will believe that we have enough courage and ability to overcome them.

Generally speaking, this sentence expresses the importance of facing the challenges and adventures in life bravely, and how this courage can help us to be stronger and more confident in our future life.