Helen Hirsch is Goeth's maid, plucked from the ranks of the Jewish girls in the camp and set to work at the commandant's villa. She's just one of the countless victims of Goeth's rage, though she survives to the end (and as of 2015 was still among the living: take that, you abusive Nazi jerk) and enjoys a modicum of safety while she's in his villa.
"Safety" is a relative term, of course, since he rapes her, beats her, and generally makes her life an ongoing psychological nightmare. She tells Oskar:
HELEN: The more you see of the Herr Kommandant, the more you see there are no set rules you can live by, you cannot say to yourself, "If I follow these rules, I will be safe."
Helen receives a simple, touching gesture of comfort from Schindler: a kiss, delivered not with lust but with compassion. A moment of kindness in the middle of her awful life that shows us fundamentally how Oskar Schindler is different from Amon Goeth. He understands her suffering and he affirms her humanity. Like the rest of Schindler's Jews, Helen ultimately defies her captor by outliving him.
The real Helen recalled that she was mystified by Schindler. She saw him carousing with Goeth and the SS on a regular basis. But one day, he took her to the window looking down on the prisoners toiling in the Plaszow labor camp. He told her to remember the Israelites in Egypt; they were slaves, but they were freed; and someday these slaves would be free, too. (Source)
Can you even imagine what that meant to her in her situation? Wow. Just wow.