Katsute no Ansatsusha wa Raise de Chigau Ikikata wo Suru

Also known as: かつての暗殺者は来世で違う生き方をする

by Yuu Okano, Tsune

Mira, once hailed as the strongest assassin, dies with bitter regrets at the hands of her rival—a young knight. However, when she reopens her eyes, she finds herself reincarnated a year later as the daughter of a noble family, bearing the same name...!? Determined to keep her past identity a secret, Mira tries to live a quiet, unnoticed life. But over time, she becomes intrigued by a way of living that's the complete opposite of her previous one—protecting others. With a newfound resolve, she sets her sights on becoming a soldier. A thrilling reincarnation tale of a rule-breaking assassin girl rewriting her destiny! (Source: Kadokawa, translated)