[1] During a March 2019 interview with Pop Crush, Sunmi described the track saying "It's about me, but I think it's a song everyone can relate to when they hear it.
[3] On August 28, the singer uploaded an interview on her YouTube channel, where she details the reasons behind the lyrics and conceptual choices for the special video.
[4] When I started making Borderline, I was quite afraid to reveal my injury from the past bcuz all the words in this song are true and honest feelings of mine.
[9] Angela Patricia Suacillo from NME noted that the song "showcases Sunmi’s ability to paint vivid imagery through her songwriting.
"[6] Many music critics noted the track for being "raw" and "emotionally honest" about something so personal to Sunmi, giving exposure and awareness to her disorder.