1. Samura wants to kill the Sword Saint, whose Enchanted Blade's Contract is connected to all the other bearers and their own blades; if the Sword Saint dies, every other bearer will die alongside him. Samura doesn't want the other bearers to die so he kills them in order to sever their contract to the Enchanted Blade and then revives them so that when he finally ends up killing the Sword Saint he would be the only sacrifice.
2. He just imagined that, she didn't actually try to commit suicide.

Im confused by 2 things :
Why would Samura try to kill the sword bearers just to severe the eternal contract if the spell will break once he dies ? He killed uruha and chihiro with the mercy of his flames so they survived but the eternal contract is no more. But once he dies, the spell will be uplifted so... what was the point ?
Second, did his daughter try to end her life when she was bullied while living with her father or was Samura just scared she would ?