Which statement best expresses the central idea of the third quatrain? your beauty will never fade, because you will live forever in the lines of this poem. love provides safety, so you should never wander from your beloved. nature is more beautiful than a poem, but also more dangerous. the beauty of summer fades when winter comes.

"Your beauty will never fade, because you will live forever in the lines of this poem."

This statement is the best expression of the central idea of the third quatrain. The central idea of the poem is "Being remembered forever or not being forgotten". Poetry is a medium if applied in the right was it externalizes the concept. The woman being praised in the poem also had the same effect of never being forgotten along with the poem. 

When you love somebody and you love a person.