Saa Himitsu wo Hajimeyou

Description

Mai, an OL who's never taken another job, is confessed to by Katou, the elite of the Sales Department. But love relations inside the company are forbidden, and if you're found out, you'll have to face severe punishment. So she rejects him once, but he, who's usually dominate and brutal, shows only Mai his real face which attracts her interest...!?

One-shots published in the series:

Tooku Koi wo Shiteru (included in volume 1)
8 months after being coldly dumped, Hana gets a call from her college ex, Tsuyoshi, just to see how she's doing. Confused, she asks her male colleague for advice and is told to be cautious about her ex's motives.

Close to You, Close to Me (included in volume 2)
Asami's prowess in bed has caused guys to run away b/c they assume she works in "that" business. She has just started dating Yuusuke, and really likes him, so to make sure he doesn't make the same assumption, she decides to...??

Otona Challenge? (included in volume 3)
Kaoru has just started dating her colleague Takanashi-san, but always feels like such a little kid next to such a capable and mature guy. Will their relationship really work when she is constantly feeling so inferior?

Darling, Darling (included in volume 4)
Ever since Tomoko's boyfriend Shin quit college to pursue his dream as a sculptor, she began feeling uncertain about their relationship. Not only did they see each other less b/c his growing fame made him busier, he seems to be slowly changing into someone she doesn't know...is it time for Tomoko to end it before she gets hurt?

(Source: MyAnimeList, Chibi Manga)