It was released as the fifth single off of her fourth studio album, Sunshine Kitty, on 18 September 2019 for digital download and streaming.

Upon release, the song received positive reviews from music critics, who complimented its production and lyrics.

[2] "Sweettalk My Heart" is a "softer-edged"[3] electropop[4][5] track composed in the key of E♭ minor and a tempo of 95 beats per minute.

[7] Lyrically, it discusses "love's deceptive, darker multitudes"[7] Upon release, "Sweettalk My Heart" received positive reviews from music critics.

Writers for website Scandipop considered the song a highlight on its parent album and Lo's fifth best single in her discography.