How sound is the story of Maria the Copt's conversion to Islam, according to the text which mentions her embracing Islam immediately upon her arrival in Medina due to what she witnessed of the trustworthiness of the Prophet's companions, may Allah bless him and grant him peace?

The story mentioned about Maria al-Qibtiyya's conversion to Islam has not been found. Two narrations have been reported regarding her conversion:

The first: She embraced Islam before reaching Medina, through the invitation of Hatib ibn Abi Balta'ah, the Messenger of the Prophet, peace be upon him, to Al-Muqawqis. Ibn Sa'd narrated that Hatib ibn Abi Balta'ah invited Maria and her sister to Islam, and they embraced it on the way. It is also narrated that the Prophet, peace be upon him, was impressed by her and ordered her to observe hijab, and that she gave birth to Ibrahim in Dhul-Hijjah of the eighth year of the Hijra.

The second: She embraced Islam after reaching Medina, through the invitation of the Prophet, peace be upon him. Al-Waqidi mentioned that the Prophet, peace be upon him, lodged her and her sister Sireen with Umm Sulaym. Then he visited them, offered them Islam, and they embraced it there. Maria gave birth to Ibrahim, while the Prophet gifted Sireen to Hassan ibn Thabit.