I feel like this is kind of spoiler-y so I'll make my one suggestion in white font to sort-of hide it: Hong Gil Dong is a goofy period/historical-setting TV show with a sad ending. It's not a hopeless ending but it's definitely a sad one and would fit your recommendation.
I agree with @Knavery. Maybe you should put a warning on the title. :) I recommend these dramas(also hidden): Cruel City, Moon Lovers: Scarlet Heart Ryeo, and 1 Litre of Tears.
My recommendations: 1 Litre of Tears 49 Days
Silence
Guilty, Akuma to Keiyakushita Onna
I'm sorry I love you
Jotei
Kamisama, Mou Sukoshi Dake Mr. Goodbye Bridal Mask