Islam as Mahr
When Abu Talha al-Ansari proposed marriage, Umm Sulaym stated her condition: she would not accept a marriage gift of gold or silver. Her mahr (bride-gift) would be his Islam. She had known him as a man who still held to idols; she made his sincere acceptance of Islam the price of her hand.
Abu Talha accepted. He accepted Islam and she accepted the marriage. The Prophet commented that no mahr was more valuable.
The Death of Her Son
Her son by her first husband died while the Prophet was away. She prepared the body, instructed the household to say nothing to Abu Talha until after he had eaten and rested, and when he asked how the child was, she answered: “He is calmer now than he has ever been.”
Only later did she tell him. She framed it to him as a question: if someone lends you something and then asks for it back, do you have the right to hold it? He said no. She said: God lent you your child and He has asked for him back. The Prophet was told this and said: “God blessed you in your night.”
The Dagger at Hunayn
At the Battle of Hunayn (8 AH / 630 CE), when some of the Muslim forces briefly broke, Umm Sulaym was present carrying a dagger. Abu Talha pointed her out to the Prophet. The Prophet asked what she had. She said: a dagger — if a polytheist comes near me I will rip open his belly with it.
See also: Seerah Khabbab Ibn Al Aratt, Seerah Sad Ibn Muadh, Seerah Zaynab Bint Khuzayma, Seerah Hafsa Bint Umar, Aisha Bint Abi Bakr