She was dressed in black when she visiting her Sweetheart's cemetery.
Although she fails to keep herself from weeping in her distress, she posses a strong sense of acknowledgement. She is already skeptical about Doctors counsellation, but when she meets Allen and learns about his similar tragic past, she decides to live the same way by keeping the loved one in her memories.
Sometime before The Traveling Clergyman she had lost her sweetheart.
The Travelling Clergyman Edit
Riza first met Allen Walker in the cemetery when she is mourning over her sweetheart. She explains him why she cries and they soon sympathize. On the Morrow, Allen visits her and gives her the bouquet prepared by Barba. They have a tea and talk about Sara, her friend who lost her own lover but managed to grieve. Then she leaves for her appointement with the doctor. He talks her into making a deal with the Earl to revive her husband but she refuses. Impatient he sedates her, but she is saved by Allen.
Although she meets Allen after her loved one has died in the novel, in the anime she meets Allen while her loved one is still alive.