Recommend a really really sad K-drama with a happy ending

Iljimae

Secret

Angel Eyes

Kill Me, Heal Me

Missing You

That Winter The Wind Blows

Sad Love Story
I actually don't remember the ending of this one.


And if you're open to non Korean dramas then:

Someone Like You (Taiwanese)

Autumn's Concerto (Taiwanese)

1 Litre Of Tears (Japanese)

Boku No Ita Jikan (Japanese)

14 Sai No Haha (Japanese)

Love That Makes You Cry (Japanese)

Also: Scent of a Woman

I second the notion's above on 
Secret
Missing You