Complex sentence: She lost confidence in Nadine who tried to modernize her act after Mattieu's "L'Américain" album failed miserably, and with the strain of Stark's legal affairs had set her back financially.
Split into simpler sentences: She lost confidence in Nadine who tried to modernize her act. The L'Américain album failed miserably, along with the strain of Stark's legal affairs setting her back financially.