Not much known about her, but her role was created by Chip as part of his happiness scenario.
One day, Sam and Castiel came to the town and met Justin and Cindy. Sam and Castiel asked about the recent suspected murder where Conrad died to them. Justin gave them to pay visit to Harrington's milkshake house for information. Cindy asked him to hurry, because her cakes may be cold if longer.
In their home, Cindy prepared from dinner. The man kept looking for the cell phone. As the loophole widen from cell phone, he realized that his cell phone was gift to her daughter Rose in Houston. Suddenly, the mind control broken. He realized that the house is not his house and Cindy is not his wife. The realization ignited predetermination means inside his head, swelling his head. Panicking and desperate to ask for help, he run from the house. His head exploded. Cindy witnessed the explosion and strangely confused.
Sam, which fell into Chip mind control, later assigned as second Justin Smith for replacing the first Justin Smith, make him as her husband. Sam, now Justin, asked Cindy to make martini.
It is unknown what happened to her later after Chip defeated, presumably her identity as "Cindy Smith" erased as well.