Later I found out why she started to hate my mother; when she was in my parents home after delivery.
After delivery she cannot do much work; so she was resting most of the time; my mother thought to kill boredom she give her some work to pass time. And my mother did`t know she do not know how to hold a needle. So my mother gave some cloths and some button to stitch, thinking she will stitch. After some time when mother returned she was trying to put thread in the needle only. Then my mother realized how much she knew about stitching. But she told me, my mother deliberately insulted her by giving her to stitch.