Is it permissible for a wife to take money from the house without her husband's knowledge to complete the price of her jewelry, which the husband had previously taken, if the agreed-upon amount was much less than the value of the jewelry?

If a person borrowed gold and promised to return it as gold, then the two parties agreed to return it as money, this is permissible on condition that the valuation is based on the price of gold on the day of repayment, and that they part ways with nothing owed between them, based on the Hadith of Ibn 'Umar (may Allah be pleased with him). The husband must return the gold by weight, or its value in cash at the price on the day of repayment. He is not allowed to force his wife to accept cash or less than her right. If the wife does not receive her full right, she is permitted to take the remaining amount from her husband's money without his knowledge. This is known as "Mas'alat al-Zafar" (the issue of gaining possession of one's right).