Betty's father and mother both know how much their daughter values the child in her belly, and it is not too much to say that they compare it to their lives.
At the beginning, Betty ruthlessly commits suicide to appease Calvin's feud with the Fea family.
But knowing that she was pregnant, she put off the idea of suicide, and it could be said that Betty survived because of the child in her belly.
Even for the sake of the child, she would rather turn her back on Calvin than have the child removed by him, even if she goes to hypnotize herself to forget that man, she still wants to keep the child.
So for Betty, the child is her life.
Yet now, she is willing to give up this child for them, how can they not be moved by this?
"Betty..." Ressie hugged her daughter heartily, "Don't worry, your father will be fine, I won't let you sacrifice yourself."