Hige wo Soru. Soshite Joshikousei wo Hirou.

[Ryllharu]

Thing is...I don't believe Gotou at all. Not about a single thing she said in the restaurant.

This is exactly the type of series that emphasizes how women lie for effect and power. Sayu's self-worth is damaged by how she's lived since she ran away. We know she's got along by sleeping with various men until they kick her out, then moves south onto the next one. They've emphasized multiple times that Sayu's smiles are an act. The convenience store girl even outright told him that all her smiles are different, implying many are lies, after confirming that he is genuine and isn't sleeping with Sayu (I got the feeling she would have reported him if he was).

Gotou's lied to him before. She's lied about taking him out for dinner so she could ask if he had a girlfriend (and assumed it was Mishima) after he obviously lost interest in her. I have little doubt she's lying about being a virgin. She watches him at work extensively, and intervened with the dinner invitation because he was getting close to Mishima.

Sayu is a very good manipulator, I assume she's played the "Um...I'm a virgin, if that's okay," card herself. But she has nothing on Gotou.

The only woman I believe is Mishima, but only partially. She's not incompetent, and can fix her own work. Wouldn't be surprised if she is deliberately fucking up to spend more time with Yoshida. Long nights, walks to the last few trains of the night, etc. But at least she isn't lying about her feelings, and wasn't lying to Sayu.

Mishima is the 'genuine' one, Sayu is in the middle, and Gotou is master class and the fakest.

edit:
If it wasn't clear that Gotou played him twice...

- She took him out to dinner, for the sole purpose of asking if he was dating someone, specifically Mashima. In exchange, he learned her cup size. It was a question-for-a-question exchange. Big prying question answered in exchange for a personal, but not exactly secret answer (which doubled as an seduction tease).

- They repeated the same same exercise this time. She leads him into the same exchange, she implies there's a reason he changed, specifically recalling their last dinner together, same table and everything. In doing so, she goaded him into asking the first question. He asks why, she gives him the 'explanation' and then she counters with a question that forces him to bring up Sayu specifically.
He gives away a huge secret, while there's absolutely no way to know if she was telling the truth.