He was probably hired by someone. I don't think he himself has any intention to kill her
Remember that one student body president who camilla exposed for bullying and had to leave the school (i forgot her name). Her dad sent an assassin group (jainer’s group) to kill her, but jainer realised how important of a figure she was and stopped. It was a couple chapters ago so i don’t remember the exact details
You are correct, they found out that the father of that student body is the one who hired the assasins, they started to investigate who dared to accept the job, it was at this time that the three big families are investigating Camilla's family, Alsian's and the read head dude (im bad with names) .. Janier acted quickly that's why they killed the one who hired them, when they are about to confront the father of the student, someone delivered a severed head like a peace offering, lmao.
Okay but why did jainer try killing her?