oooo I know it... Its from the episode battleground earth.

Clark: Marry me, Lois. Let's not plan, let's not wait . . . Let's not have any clone-makers or psycho-psychiatrists, or women who shrink people into little people keep us apart. Just marry me.

Lois: You know . . .that's precisely what I was thinking!

Being grown-up isn't half as fun as growing up, these are the best days of our lives, the only thing that matters is just following your heart and eventually you'll finally get it right! ~Ataris