Oil on canvas can show reality, but truth will not be found in a realistic painting. No, truth hides in expressions of pain, fear, love, awe, and even hatred. Such strong feelings rapture the viewer and rupture their heart. Only feeling can convey truth. To be creative is not to create. It is to feel. Creativity is not a desire, it is a command to represent what you feel in what you make.
Successful artists are rarely happy. The depth of emotion necessary to create riveting artwork is not often found in joy. Creating truth requires shadow. It requires darkness. It requires exploration into the deep and murky waters of the mind. You do not reach mastery of art until you have achieved mastery of the self. Success is not fame. Success is reaching and recreating such truth, such beauty, and such pain that you have depicted reality in its rawest form.