심박수 (shimbaksu) directly translates to "heartbeat" or "heart rate." While not extremely rare, it's a more specific and evocative word than common terms for emotions, making it stand out.
In "Supernatural," the phrase "내 심박수를 믿어" (nae shimbaksureul mideo) means "trust my heartbeat." It's used to convey a deep, instinctual connection and a sense of destiny, suggesting that the physical reaction of a racing heart is a reliable guide to their fated relationship. This gives the word a romantic and compelling weight within the song.
Three languages take turns inside this song and none of them is decoration. The Korean carries the argument: "우리 인연은 깊어" [our bond runs deep] leans on 인연, the word Korean keeps for a tie that was already in place before you met the person. The Japanese answers it, which makes sense because Supernatural was NewJeans’ Japan debut single: "もう知っている" [I already know], then "見つけられるよ" [I can find it]. The English does the scenery, "Golden moon, diamond stars", and the two of them keep arriving under it.
The line worth arguing with is "내 심박수를 믿어" [I trust my heartbeat]. Nobody is asking for proof. A pulse has already been accepted as evidence, which is why "I gotta see the meaning of it" reads less like doubt and more like someone catching up to a conclusion they reached ages ago. By the bridge the hedging is gone: "거짓말 안 할래, 너도 말해" [I won’t lie, you say it too]. That is what the title is for. When you cannot account for the thing, you call it supernatural.