Chuuhai Lemon: LOVE 30S

Overview

When Gorou Tatsumi, a burly undercover police officer at Shinjuku station is hit upon by a unsuspecting hooker, both of their lives take a totally unexpected turn. Before long Tatsumi and the hooker fall in love with each other but a jealous former client of the girl doesn't approve and as tensions escalate, Tatsumi finds himself the victim of a vicious knife attack. Only the girl can find out who the culprit is but, how will she do it?

Source: AniList