Natalia

Though Flowers of War quite a lot heavier to watch than Battle of Changsha. They both take place during the Japanese invading China, with similar themes of war, love, sacrifice, sadness, and hope.

Both female leads...
fake their identities,
forced to live with a stranger's family,
fall in love with one of the strangers in the family,
have one younger brother,
are poor...

Along with some other similarities.