Hermann, son of the wealthy innkeeper in a small town near Mainz, is sent by his mother to bring clothes and food to the refugees which have set up camp near their town. They have fled their villages on the western side of the Rhine river, now occupied by French revolutionary troops, in order to seek refuge on the eastern side. On his way to the camp, Hermann meets Dorothea, a young maid who assists a woman in her childbed on her flight. Overwhelmed by her courage, compassion, and beauty, Hermann asks Dorothea to distribute his donations among her poor fellow refugees.
Back home, he reveals his affection to his parents. His father brushes away his timid confession, reminding him bluntly that he wants Hermann to choose a wife from a respected local family with a generous dowry. He goes on to express his deep disappointment with Hermann's perceived lack of ambition to move forward in life, and lectures him about how he should become a respected citizen.
After Hermann has left in despair, his mother utters the following timelessly wise and deeply moving verses:
Immer bist du doch, Vater, so ungerecht gegen den Sohn! und So wird am wenigsten dir dein Wunsch des Guten erfüllet. Denn wir können die Kinder nach unserem Sinne nicht formen; So wie Gott sie uns gab, so muß man sie haben und lieben, Sie erziehen aufs beste und jeglichen lassen gewähren. Denn der eine hat die, die anderen andere Gaben; Jeder braucht sie, und jeder ist doch nur auf eigene Weise Gut und glücklich.
Why will you always, father, do our son such injustice? That least of all is the way to bring your wish to fulfillment. We have no power to fashion our children as it suits our will; As they are given by God, so we must have them and love them; teach them as best we can, and let each of them follow his nature. One will have talents of one sort, and different talents another. Every one uses his own; in his own individual fashion, each must be happy and good.
Hermann's mother goes after her son and finally finds him in a far corner of their garden. Having been shaken to tears by his father's harsh words, Hermann tells his mother that he intends to marry Dorothea or else to stay bachelor for the rest of his life. His mother understands the sincerity and depth of his affections and decides to help him obtain his father's permission. They return to Hermann's father, who still discourses with his respected neighbors, the town's pharmacist and the young and wise parish priest. The two friends offer to collect inquiries among the refugees to find out if Dorothea is virtuous and worthy to be Hermann's bride. Moved by his wife's and friends' persuasion, Hermann's father grudgingly promises that he will abide by his two friends' recommendation.

Question: How did his mother promise to help Hermann?
Answer: By helping him get his father's permission
Alternative answer: to convince his father to let him marry Dorthea