"This I Promise You" is a song by American boy band NSYNC. It was released on November 25, 2000 as the third single in the United States and the fourth single in Europe from their second studio album, No Strings Attached, in 2000.

The song was composed by pop singer Richard Marx, who would later record the song twice, first for the Japanese release of his album Days in Avalon similar to the NSYNC version, and again as a rock song for the European version of his Stories to Tell album. Marx would later use the Days in Avalon version of "This I Promise You" for his Now and Forever: The Ballads album as a duet with Asian singer Sabrina.

"This I Promise You" was the group's fifth top-ten single in the U.S., reaching number five on the Billboard Hot 100 chart in the autumn of 2000. In addition, the song spent 13 weeks at number one on the Billboard Adult Contemporary chart, the group's first song to do so. The single was less successful internationally, reaching number 21 on the UK Singles Chart and failing to make the top 20 in Australia.

The album version of the song was also featured on the 2001 compilation album Now That's What I Call Music! 7, but the radio edit was featured on all the three compilation albums: Greatest Hits (2005), The Collection (2010), and The Essential *NSYNC (2014).

A Spanish language version of the song, titled "Yo te Voy a Amar" was recorded at the same time and released in Spanish-speaking countries such as Mexico and Spain.

...
Wikipedia