Lene's career started with Unforgivable Sinner. In August 1998 the song was played for the first time on local radio stations, when Lene turned 18. On October 12th the single was officially released in the Norwegian market, and in a few hours all the copies were sold out: success was huge and on October 21 the single was number 1 in the Norwegian chart. Unforgivable Sinner is the best-selling single in Norwegian history. It was also on the soundtrack of "Schpaa", an important Norwegian movie, directed by Erik Poppe. The first video for Unforgivable Sinner was shot in Oslo before the release of the single: Lene's dressed like an angel, and there are clips from that movie. The single was released in Japan (#1 in the chart), Denmark, Sweden and had good success. In March 1999 Unforgivable Sinner came to Italy and managed to get to number 1, that's the best debut Lene could have had in Italy. The international version of the video was shot in a train station in Toronto, Canada, and all the colors are in blue tones. Lene didn't have the same success in England as she had elsewhere: the single had no promotion, and it was unnoticed; but Virgin re-released the single (in two different versions) on September 4th 2000, after many postponements and especially after Sitting Down Here's success. This time there was a new video, filmed in the USA (New York), where Lene showed herself with black hair. Unforgivable Sinner debuted at #13 in UK single chart, and that was its highest position.

UNFORGIVABLE SINNER
Pubblicato in: Norvegia (1998)
1.	Unforgivable Sinner	4:02
2.	Maybe I'll Go	4:37

UNFORGIVABLE SINNER
Released in: Europe (1999)
1.	Unforgivable Sinner	4:02
2.	Maybe I'll Go	4:37
3.	The Way We Are (live acoustic version)	4:50
Words & Music by Lene Marlin Produced by Hans G. e Jorn Dahl All vocals by Lene Marlin All keyboards & programming by Jorn Dahl Guitars by Stray except: "Maybe I'll Go" by Lene Marlin Bass by Wallen Mjaaland Piano by Jorn Dahl

UNFORGIVABLE SINNER
Released in: England (1999)
1.	Unforgivable Sinner	4:02
2.	Maybe I'll Go	4:37
3.	The Way We Are (live acoustic version)	4:50

UNFORGIVABLE SINNER [CD1]
Released in: England (2000) CD1 release date: 04/09/2000
1.	Unforgivable Sinner	4:02
2.	Unforgivable Sinner (Tin Tin Out Mix)
3.	Maybe I'll Go
4.	Unforgivable Sinner (video v3)

UNFORGIVABLE SINNER [CD2]
Released in: England (2000) CD2 release date: 04/09/2000
1.	Unforgivable Sinner	4:02
2.	Unforgivable Sinner (Disclab Dodgers Doorstep Mix)
3.	The Way We Are (Live at Sound Republic)
4.	Unforgivable Sinner (video v2)
Includes a poster