First of all,what is mentality?
It is the the characteristic way of thinking of a person or group.
To get the idea what is mentality,we should consider lion(king of jungle).
Lion is not the biggest of animal in jungle.the biggest animal of all is elephant but it is not the king of jungle.
Lion is not the fastest.The fastest as we all know is cheetah.
Lion is also not the smartest.its got to be the fox.
The thing which makes lion king of jungle is mentality.
When lion comes across pack of hyenas,lion does not fear because of its strong mentality which makes it king of jungle.
So,with strong and positive mentality we can be the king of our world.
very good article