Stephen Jay Gould, the well-known scientist who suffered from a rare form of cancer wrote this:

I asked Sir Peter Medawar, my personal scientific guru and a Nobelist in immunology, what the best prescription for success against cancer might be.

‘A sanguine personality,’ he replied.

Will save ya a trip to the dictionary.  This is from Webster’s:   

San´guine: 

Anticipating the best; cheerfully optimistic; not desponding; confident; full of hope; as, sanguine of success; a sanguine disposition.”

If only it were so easy.