Samantha Stein-Wells has waited more than two years for this day.

Jury selection begins today in the trial of the woman accused in the savage slaying of her mother, “Realtor to the Stars” Linda Stein, who was bludgeoned to death in her Fifth Avenue penthouse.

“I’m going to be [in Manhattan Supreme Court] every day until justice is served,” Stein-Wells said.

Stein’s pretty, young personal assistant, Natavia Lowery, accused in the slaying, insists she’s innocent.

Cops suspect that on Oct. 30, 2007, Stein opened her mail — a task she usually left for Lowery — and was shocked to find thousands of dollars in bills Lowery had rung up in Stein’s name.

They believe an argument escalated between the broker to such A-listers as Madonna, Calvin Klein, Angelina Jolie and Elton John, and the prim, 28-year-old Hunter College business graduate.

Stein, 62 — a punk-rock pioneer who managed the Ramones before switching to the cutthroat world of multimillion-dollar real estate — was as fierce in her anger as she was in her loyalty to friends. Even so, prosecutors say, she was no match for Lowery.

“I felt like she was my worst enemy,” Lowery said in a videotaped confession.

The defense insists it was coerced. Laura Italiano