Muhammad bin Ishaq (may Allah have mercy on him) said: I was informed that the guardian in the marriage of Sayyidah Umm Habibah (may Allah be pleased with her) was her cousin, Khalid bin Sa'id bin al-As (may Allah be pleased with him).
The Shaykh (may Allah have mercy on him) said: He was the son of her father's paternal cousin, because Sayyidah Umm Habibah (may Allah be pleased with her) is the daughter of Abu Sufyan bin Harb bin Umayyah, and al-As is the son of Umayyah.
(b) It has also been said that Sayyiduna Uthman bin Affan (may Allah be pleased with him) was the guardian of her marriage.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النكاح / 13798