Who said "My song is simple but true."?

This quote is attributed to Groot (Variant).

My song is simple but true. - Groot (Variant)

"My song is simple but true."

Groot (Variant) Truth

"I am Groot."

"We are Groot."

"I am Groot. I am Groot. I am Groot."

"The greatest gift is the time we spend together."

"Lucy, you got some 'splainin' to do!"

"You must always be honest with the people you love."

"Truth always comes out in the end."

"Honesty is always the best policy."