A promissory acceptance would also have given Edyth what she wanted. If Richard and Frances had said, in response to the offer, "We promise to continue to take care of you," Edyth, who loved and trusted them both, would have been able to count on their continuing to take care of her.
True or False - So, again, she would have gotten what she wanted: the bestowing of a reward and the knowledge that Richard and Frances had an additional motive to continue to take care of her.