Is it permissible for a guardian to marry his female ward with her permission, knowing that she has no male guardian from her agnates or maternal relatives?

For a marriage to be valid, it must be contracted by the woman's guardian (wali) or his proxy, based on the Prophet's (peace be upon him) saying: "There is no marriage except with a guardian," and his saying: "Any woman who marries without the permission of her guardian, her marriage is invalid." If she does not have a Muslim guardian, a Muslim judge marries her, based on the saying: "If they dispute, then the ruler is the guardian of one who has no guardian."

You have erred by appointing yourself as the woman's guardian, given the presence of Muslim judges in your country. You both must re-contract the marriage. If the judges in your country adopt the view that a woman may marry herself, it is safer for both you and her to entrust her guardianship to one of the Muslims, who then performs her marriage to you. A woman's guardian may marry her if she consents to him.