Her mother always kept a calm front and assured her that she didn't know any grudge when, in reality, she couldn't let go of the bitterness she was holding.
The conflict of not being able to hate her child and blaming her child for the death of her lover made Betty's mother choose the safest and easiest option.
One which, once chosen, would result in Betty's mother being free of the oppressive life.
When Sebastian got to know about Betty's mother's death, he was devastated. Ironic as it may seem, instead of blaming himself or the family who had forced Betty's mother to commit suicide, he blamed Betty for everything.
To torture her, the mistress whom he didn't even like much, and the daughter of the mistress, who clearly wasn't related to him, he brought them into the mansion and even married them.
Oftentimes, Betty thought that Sebastian was using her as a shield to get together with his first love.
