Gun Tobasareta node Nirami Kaeshitara, Aite wa Koshaku-sama deshita. Kore wa Mazui

Overview

Angelica, a former yankee delinquent who’s been reincarnated as a noble young lady in another world, survives her sister’s etiquette training and somehow reaches her debutante—but at the party she feels a man’s eyes on her and instinctively glares back. Unfortunately, the man is a coldhearted duke! Just when she thinks she’s picked a fight with someone way out of her league, the duke, for some reason, finds his heart fluttering at Angelica’s fiery stare?! (Source: Kadokawa, translated)

Source: AniList