Mara danced at Jabba’s Palace

"I'm sure I'd remember you if we'd met."

"Oh, right," she said sardonically. "The great, omniscient Jedi. See all, hear all, know all, understand all. No, we didn't actually meet; but I was there, if you'd bothered to notice me. I was a dancer at Jabba the Hutt's palace the day you came for Solo."

So that was it. She'd worked for Jabba; and when he'd killed Jabba, he'd ruined her life...

Luke frowned at her. No. Her slim figure, her agility and grace—those certainly could belong to a professional dancer. But her piloting skills, her expert marksmanship, her inexplicable working knowledge of lightsabers—those most certainly did not.

Mara was still waiting, daring him with her expression to figure it out. "You weren't just a dancer, though," he told her. "That was only a cover."

Her lip twisted.

"Very good. That vaunted Jedi insight, no doubt. Keep going; you're doing so well. What was I really doing there?"

Luke hesitated. There were all sorts of possibilities for this one: bounty hunter, smuggler, quiet bodyguard for Jabba, spy from some rival criminal organization...

No. Her knowledge of lightsabers... and suddenly, all the pieces fell together with a rush.

"You were waiting for me," he said. "Vader knew I'd go there to try and rescue Han, and he sent you to capture me."

"Vader?" She all but spat the name. "Don't make me laugh. Vader was a fool, and skating on the edge of treason along with it. My master sent me to Jabba's to kill you, not recruit you."
- Heir to the Empire