The name is Qatam bint Shajna

She was a woman from Kufa who played a role in motivating Ibn Muljam to martyr Imam 'Ali .Since her brother and father were killed in the Battle of Nahrawan, she conditioned her marriage with Ibn Muljam upon the murder of 'Ali (a). Qatam was famously very beautiful, and her condition for marriage motivated Ibn Muljam to murder Imam 'Ali (a).

Note that Some contemporary scholars take this story to be fictional and not authentic . Hence you don’t hear about her.