In her letter, what does Annie say is her greatest problem with Helen?

In her letter, Annie says that the greatest problem she has with Helen is how to discipline her young charge without breaking her spirit.
Annie maintains that, thus far, no one else has tried to control Helen, and she sees it as a daunting task to do so. As Annie writes her letter, Helen has dumped out all the contents of her bottom bureau drawer so that she can tuck her doll into the drawer. Then, looking for something else to engage her attention, Helen soon turns to the items on Annie's desk. While groping about the desk, Helen knocks over the inkwell, and Annie has to grab a towel to clean up the spill.
To engage her charge, Annie then gives Helen a sewing card, needle, and thread. However, Helen soon pokes herself with the needle. To express her fury at her pain, Helen dashes her doll forcefully against the floor. Hurriedly, Annie spells "bad girl" onto Helen's hands and then demonstrates what a "good girl" does with her doll. Helen seems to understand, but she doesn't stay idle for long.
In a short moment, Helen picks up a pitcher and dashes it against the floor instead, fragmenting the pitcher into pieces. It appears as if Helen has learned to be careful with her doll but has yet to learn how to be careful with other things in the house.