Honestly I don't like how this went. In fact, I down right hate it. Sure Sae-Mi needs a push, but this had a very high chance of backfiring. If Sae-Mi had decided to support Yena like they had promised(Which honestly speaking, Sae-Mi totally should of done that based on her character.) then Sae-Mi may have very well ran off to go cry somewhere far enough where her shrieks of despair wouldn't be heard by them, and Yena would've been left behind knowing she fatally wounded her best friend while also knowing there was no way for her to catch up to Sae-Mi due to her monstrous strength and speed. It's fortunate this is more comedy than drama, but the drama tag is still there and things totally could have gone south real hard. I mean, Yena was basically betting on Sae-Mi being too jealous to think of Yena's (fake)feelings for Young-Min, thus making Sae-Mi out to be a petty bitch who kept thinking of ways to prevent Yena from confessing. I don't think I hate Yena, but her appeal definitely went down after this. There had to be some better way to do this, and the fact that Miss Smartypants Yena couldn't think of another way is some bullshit.
On the flip-side, there is still the fact that she wasn't lying about the person she liked being nearby. Given that it's not Young-Min then it's possibly a yuri development with either Sae-Mi or Mia. Or just platonic love for her friend Sae-Mi. I'd still prefer the yuri route despite the shit she put Sae-Mi through.
Seriously though, fuck this manipulative bullshit. Here's to hoping for a lot more fluff in the coming chapters to make up for it.