Joy Morgan smiled and laughed as she was interviewed by a fellow church member, in a recording played during the trial of the man accused of murdering her.
The 20-year-old read her favourite piece of scripture and said she had been left "mindblown" by the church's teachings, in footage taken on December 15 last year.
She went missing after a church event on December 26 and has not been seen since.
Shohfah-El Israel, also a worshipper at the IUIC church in Ilford, denies killing her.
A jury at Reading Crown Court was played footage of the short video on the first day of the trial on Tuesday.
Ms Morgan, when asked in the footage why she is a member of the church, responded: "IUIC is my family and, like, the best family that I've ever had."
She said that by January 2019, she would have been a member of the church for three years.
Ms Morgan said she had been looking into the Illuminati and came across a suggested video of the IUIC, adding: "From then, I was mindblown."
She said she had been excited at "finding out that Christ was a black man".
"At no point in my entire life did I ever think Christ might be a black man," she said.
The court also heard a recording of a phone call between a police investigator and Israel.
The call, on February 8, came a day after Ms Morgan had been reported missing by her mother.
Israel, who was with his wife during the call, told Maria Fernandez from the Hertfordshire Police missing persons unit that their "primary concern" was Ms Morgan's safety.
He said: "Our primary concern is her, to find out, make sure she's OK, that is our primary concern."
Chindu Nwankwo said her husband had dropped Ms Morgan off at home after the church event on December 26.
Israel told Ms Fernandez, in a call that was partly recorded by the defendant or his wife, that the couple had gone to check up on Ms Morgan three days later on the Saturday.
Mrs Nwankwo said a housemate of Ms Morgan's had told them that while they had not seen her in a while, her laundry was in the machine the previous night.
The defendant's wife added: "So that means that she was there on Thursday."
Israel said he returned later that day with a "brother" from the church to check again to see if she was in, but when they got no answer they left a contact number with another housemate.
Mrs Nwankwo said Ms Morgan's apparent departure from the church - signified by her number being removed from a Telegram chat group - had been a shock.
She said: "Her taking herself away from the church shocked almost everybody as far as I know."
Israel was arrested by police the day after the phone call.
Ed Brown QC, representing Israel, put it to Ms Fernandez, who was in court for the recording, that the cases of some missing people "remain a mystery".
He said: "A large number of people are reported missing, whether it be in Hertfordshire or other urban areas, and some are not found, that's the reality?
"Some of those who are not found just remain a mystery don't they? It (the report) remains open but it remains, for the time that it's open, a mystery ultimately?"
Ms Fernandez replied: "Yes."
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