How sound is the hadith which states that whoever says "None has the right to be worshipped but Allah, the Sovereign, the Manifest Truth" a hundred times a day will be safe from poverty, will knock on the door of richness, and poverty will be kept away from him?

The hadith (definition) was narrated by Al-Daraqutni with similar wording to what was mentioned, and it has two narrations:

The first: The narration of Salam bin Al-Mughirah, who is weak, from Malik, from Ja'far bin Muhammad, from his father. Muhammad bin Ali is among the younger generation of Tabi'in, so the hadith is mursal (lacks a companion in its chain of narration). Thus, it combines the weakness of Salam and the issue of irsal.

The second: The narration of Al-Fadl bin Ghanim from Malik, from Ja'far bin Muhammad, from his father, from Ali. Al-Fadl is weak, and there is a break in the chain between Muhammad and Ali.

All those who narrated this hadith from Malik are weak. Al-Khatib mentioned it from Al-Fadl bin Ghanim, from Malik, from Ja'far bin Muhammad, from his father, from his grandfather, from Ali. However, Muhammad did not narrate from his grandfather, so there is a break in the chain and the weakness of Al-Fadl bin Ghanim.