Sharaban K, 24, and a 25-year-old man are alleged to have selected the victim for her looks and age.
Prosecutors say she had then planned to go into hiding and start a new life but was caught the next day.
She and her alleged accomplice deny the charges.
According to court papers, German-Iraqi Sharaban K, who was 23 at the time of the murder in August 2022, had sought out women who looked like her on Instagram and then tried to meet them though various promises.
Prosecutors say the victim, a 23-year-old woman of Algerian origin called Khadidja O, was promised free treatment at a beauty salon.
She was picked up in the town of Eppingen in southern Germany and then driven, allegedly by the two accused, towards Ingolstadt in Bavaria.
On the way, prosecutors say the victim was stabbed 56 times and hit over the head before her body was abandoned in a forest in Sharaban K’s black Mercedes car.
When her body was discovered, it was initially thought that Sharaban K herself had died. However, she and the 25-year-old, Sheqir K, were arrested as suspects in the case the next day after being spotted in a local pizzeria.
Sharaban K’s family are said to originate from a Yazidi community in northern Iraq and German media report that her failed marriage may have been the motive for her to attempt to fake her own death.
After examination of further evidence, including interviews with witnesses and chat logs, police brought further charges against the pair.
The pair are also suspected of hiring a contract killer to murder her former partner’s brother. However, the alleged hitman, who received a deposit of €5,000 (£4,230), did not carry out the killing.
In addition, while in custody, the male suspect is said to have attempted to persuade an inmate to kill witnesses in the case.
Proceedings on the trial’s first day on Tuesday were significantly delayed. Defence lawyers argued that no fair trial was possible as prosecutors had recently submitted additional documents which the defence needed additional time to examine, and requested a suspension of proceedings.
The prosecution rejected the argument, saying it was not unusual for additional documents to be submitted after an indictment.
The court is expected to rule on whether to suspend proceedings next week.
