"Tomorrow morning, she will help me tidy the house."
Translation:Demain matin, elle m'aidera à ranger la maison.
Because "nettoyer" is "to clean" whereas "ranger" is "to tidy." "To wash," "to clean" and "to tidy" have different meanings in French as they do in English and they're not interchangeable. Although you might well say that you're going to clean the house, that's not what the exercise was asking you to translate.