Because you have to believe that there's someone out there for you who won't leave you in the desert but will chase after you and stay with you to find a source of water.
You have to believe that someone out there will dread to see you die.
You have to believe that someone out there will share a pot of gold with you.
You have to believe that there would be someone out there to hold a rose for you and take you out on a date to see a Shakespearean play and treat you to a can of coke afterwards.
I know that there's no guarantee that you will find that someone. And it gets tiring to wait.
But do yourself a favour and just believe.
It is sure as hell better than waiting for someone who would do nothing while you're held at gunpoint to come around.
Just believe that there's someone better for you out there.
And believe that happy ending is near and your tears will wiped away in time.