Answer:
In these lines, Mrs. Van Daan uses a sad and pitiable tone.
The word that suggests that tone "killed myself"
Her tone makes the reader to feel so sorry for her and wonder why Peter doesn't care about his mother.
Step-by-step explanation:
From the given passage, one will discover that Mrs. Van Daan's tone was sad and pitiable. She tends to reveal to the audience how she has been abandoned and neglected by her son. She revealed that her son doesn't care if she killed herself.
Her words like "...killed myself" makes one to feel for her and wonders which son will actually abandon his mother without caring what happens to her.