In "The Rocking Horse Winner", what does the passage below tell us about Paul's mother? "Two nights before the Derby, she was at a big party in...

At the beginning it states that "when her children were present, she always felt the centre of her heart go hard." This is why the passage you provided is so interesting.  It describes that "one of her rushes of anxiety about her boy, her first-born, gripped her heart till she could hardly speak."  How could such a cold woman feel such anxiety for someone that supposedly made "the centre of her heart go hard"?  The statements directly contradict each other. 

Paul's mother, upon feeling this intense anxiety, "fought with the feeling, might and main, for she believed in common-sense".  For some reason, feeling love and concern for her son was not sensical to her, perhaps because she didn't feel it very often.  She puts ridiculous excuses in front of her concern, like "She did not want her son's privacy intruded upon" when she calls to check on him.  The author seems to be condemning of her idea of common sense.  If she is worried, common sense would dictate that she act on it, not maintain her public face, which is what she does.  She is a woman full of good intentions but no follow-through, no real sense for what is important.  From the beginning we realize she is obsessed with money, but not enough to change her lifestyle.  In this passage, we see her worried about her son, but not enough to do something that really matters about it.