What does it mean to have a heart of a lion?
It means to be brave fearless in the face of great odds. To be courages and to simply be who and what we are regardless of others opinions or our own fears.
We see it all the time in movies and in real life. There's always that one person that had everything to their advantage, was smart, and had skills, but they just didn't have the heart to keep fighting for what they wanted or get the job done Then there's someone who isn't as strong, as talented, didn't have much to their advantage but no matter what they refused to give up. They keep going no matter what. This trait of heart can push you to overcome and win.
In order to have a heart of a lion, you first need to believe in yourself. Your mind is a "thought factory". It's busy producing countless thoughts in one day. You can let your mind manufacture thoughts why you can't, why you're weak and why you are inadequate or you can specialize in producing thoughts why you can and why you will.
Think success, don't think failure.
Think I'll win, not I'll lose.
Think I'm equal to the best not I'm outclassed.
Say I can do it, not I can't.
Remind yourself regularly that you are better than you think you are. Successful people are not superman. Success does not require super intellect. Success is not based off of luck. Successful people are just ordinary folks who have developed self belief in themselves and what they do. They have developed a heart of a lion.