天荒地老纯属童话海枯石烂纯属扯淡
[tiān huāng dì lăo chún shŭ tóng huà hăi kū shí làn chún shŭ chĕ dàn]
These expressions usually refer to vows of eternal love that never change even when heaven and earth age (‘天荒地老’) or oceans run dry and stones crumble (‘海枯石烂’). However, this person thinks these promises aren't realistic, just fairy tales and empty talk without foundation. It reflects skepticism towards the concept of eternal commitment.