Who said "I'm gonna try really hard to be a better person."?

This quote is attributed to Butters Stotch.

I'm gonna try really hard to be a better person. - Butters Stotch

"I'm gonna try really hard to be a better person."

Butters Stotch Perseverance

"I'm not bad, I'm just drawn that way"

"Aw, hamburgers!"

"You're grounded, mister!"

"I have to go do my chores now"

"Perseverance is the key to success."

"Don't give up on what you believe in."

"I've been through worse."

"You learn to live with the pain."