If the guardian himself is the suitor

Narrated Sahl bin Sa`d: While we were sitting in the company of the Prophet (ﷺ) a woman came to him and presented herself (for marriage) to him. The Prophet (ﷺ) looked at her, lowering his eyes and raising them, but did not give a reply. One of his companions said, "Marry her to me O Allah's Messenger (ﷺ)!" The Prophet (ﷺ) asked (him), "Have you got anything?" He said, "I have got nothing." The Prophet (ﷺ) said, "Not even an iron ring?" He Sa`d, "Not even an iron ring, but I will tear my garment into two halves and give her one half and keep the other half." The Prophet; said, "No. Do you know some of the Qur'an (by heart)?" He said, "Yes." The Prophet (ﷺ) said, "Go, I have agreed to marry her to you with what you know of the Qur'an (as her Mahr)."