I just saw this on tiktok but I can't remember the title of this manhwa. It's about a girl...

I just saw this on tiktok but I can't remember the title of this manhwa. It's about a girl who enter a fake relationship with this boy but the boy like the mc's friend. I think they're in a yatch or a ship or something and then there's an accident that happened the mc and the friend are drowning (I'm not sure). The mc saw the boy trying to save her friend and then she had a moment of realization and shits. Please tell me the title of this