The song was written by the singer, Harmony "H-Money" Samuels and Timothy and Theron Thomas of the production duo Rock City.

A slow-tempo, somber R&B ballad—with sparse, throwback 1990s-style R&B production—"I Bet" shifts from the sound of the singer's later discography to recall her earlier works, "And I" (2005) and "Promise" (2006).

"I Bet" was well received by music critics who deemed it a strong comeback for the singer, and commended her vocal range, as well its rare and honest showcase of her private life.

Described as a realest, scathing breakup song, a variety of publications opined that the ballad was written about Ciara's break-up with Future as a diss track, and noted that it was the first time the singer weighed in on their split.

[3] Following their very public break-up, Ciara's album release was further postponed to 2015,[2] and during this time the singer "quietly" recorded new music, while concentrating on motherhood.

Following its premiere, publications noted that the release of the song was reminiscent of Ciara's 2012 single "Sorry", which also served as a comeback for the singer in the form of a ballad.

[10] The track serves as the lead single from Ciara's upcoming sixth studio album, Jackie,[6] and was released by Epic Records as a digital download on January 26, 2015.

[16] Comprising snapping snares and canned synths,[17] it is accompanied by throwback 1990s-style R&B production, and includes the use of string and keyboard instrumentation, and a steady beat.

A quiet, contemplative and deeply personal record, "I Bet" moves away from the sound of Ciara's later discography and recalls some of her earlier work,[18] namely "And I" (2005),[3] and "Promise" (2006).

[3] "I Bet" goes through the motions of feeling bitter,[9] by acting as a callout of her former love interest's new girlfriend, manifested in the line, "Is that your bitch over there givin' me the ugly stare / The one with the silicone ass and the Brazilian hair".

[3] Later in the song, it is revealed that in the situation, Ciara is not as boastful as the chorus would suggest; and tells a story of the pain of finding a new lover when her future was planned with her former one.

[25] While Larry Fitzmaurice of The Fader noted that the track's cutting lyrics also depicted that there was no love lost between Ciara and Future, and opined that the lines—"I mean, I would stay if you could tell the truth / But you can't / No matter how much time I ask"—served as a "seriously withering burn" in the former couple's relationship.

[18] Complex's Justin Davis commended Samuels' production on the track for providing Ciara with "plenty of instrumentation to show off her impressive vocal range".

[2] Digital Spy's Lewis Corner and Amy Davidson described the ballad as "a nice and smooth introduction of what's to come," adding, "['I Bet' is] a soft launch of sorts, suitably hyping us up for what is still to come".

[26] Nolan Feeney of Time commented, "Let's hope the Jackie album campaign has more luck than her personal life [because 'I Bet'] deserves better".

[9] Emily Tan of The BoomBox shared Gracie's view, writing, "Since [Ciara's] known to be on the private side, we're pleased to hear her get in touch with her emotions here".

"[20] Simarly to Stereogum's Breihan, Lindsey Weber of New York Magazine compared "I Bet" with Future's break-up song, "Just like Bruddas".

[30] Following its rhythmic contemporary impact date in the United States on January 27, 2015, "I Bet" became the second most-added single on the format with 25 adds in its first day.

"I Bet" was certified Platinum by the Recording Industry Association of America (RIAA) for sales of over one million units in December 2015 and was the only female R&B song released in 2015 to earn this achievement.