Poor Sakuma/Ema/Naruse got turned down in three different ways from their perspective
Turned down how? Houjou had other commitments, which SEN absolutely knows, because SEN was the other commitments. 'Sakuma' was the only one who had time, and alcohol + Houjou's ethics closed anything there that night.
Each "persona" had an active ask to spend more time with Houjou, which I believe was meant to make her choose who she liked best under the assumption that she would cancel the other dates if she had accepted Naruse or Ema's invitations. Houjou turned the first two down, so they assumed Sakuma might be the one that she liked the most, and was the most forward after the dinner.
Sakuma clearly was not drunk, so when she embraced Houjou/went for a kiss she was hoping to potentially be taken back to a hotel by Houjou, but instead Houjou who (as has been previously established) is terrible at reading romantic cues, assumed that Sakuma had stumbled and had too much to drink and politely brushed them off to allow Sakuma to save face. In a business environment this makes perfect sense, when someone makes a mistake you politely give them an off ramp to maintain their reputation, but in the context of a romantic date, it reads as a rejection of that intimacy, which you can tell by the fact that Sakuma goes completely red in the face because she's embarrassed at her overture being rejected. But of course that only registers as being drunk in Houjou's mind.