I agree with DG. Trying to memorise words is really not a productive way of learning. 100 words a week? - yeah, right.

What is the point of 'learning' a word if you are incapable of using it in your writing or unable to understand it in a different context? Plus there are nuances of meaning which you simply will not grasp through flashcards. Learning vocab dry is what you do when you are teaching yourself a foreign language.
Reading is the key. You need to persevere and try and find something she enjoys which should lead to other things. There is a massive world of books and literature out there. There are more resources than ever before available to children (as well as adults). The best memory in the world will really not help your child write in an engaging and expansive way for her composition.