She knows Obi-Wan's real name as well as his alias of “Ben.” When Luke comes barging into her cell and says, “I'm here with Ben Kenobi,” Leia jumps off the bunk in an instant. “Ben Kenobi, where is he?” she says, raring to go. That name was all she needed to hear.
The most straightforward explanation would be that Leia knows the person who rescued her is Ben, and never connected the dots that Ben is actually Obi-Wan. Surely complicating matters is that various characters have referred to him as Obi-Wan in her presence.
Obi-Wan came to the Death Star to save Leia from the Empire's clutches, but was killed by Darth Vader while the others were busy escaping. Leia didn't see Obi-Wan again, nor did she experience any sadness when she learned of his death.
On Tatooine, the droids are captured and sold to Luke Skywalker's uncle. As Luke is cleaning R2-D2, he accidentally triggers part of the message from Princess Leia, which plays on repeat. "Help me, Obi-Wan Kenobi," she says, "you're my only hope."
And as Obi-Wan spends time with young Leia, he can't help but note how much she reminds him of her parents. “Princess Leia Organa,” Obi-Wan addresses her in the finale. “You are wise, discerning, kindhearted. These are qualities that came from your mother.
Darth Vader only learned he had a daughter in Return of the Jedi - but there's no evidence he realized she was Leia before his death and redemption. Darth Vader may have never known Princess Leia was his daughter in Star Wars and never cultivated a relationship with her, even when he was a Force ghost.
Leia told Luke she had “images” and “feelings” about her mother, same as Obi-Wan's “flashes” of his family. So Leia wasn't lying or imagining things in Return of the Jedi. And the plot hole created by Revenge of the Sith is no more. Leia really did have memories of Padmé, even if Luke didn't.
However, Leia's strong-mindedness during Vader's probe denied him the opportunity to discover she was his daughter. That serves to justify Vader's lack of awareness of his connection to Leia, although, perhaps, not as satisfyingly as if Lucas had planned for the relationship from the beginning.
While in Tatooine's seedy Mos Eisley cantina, Chewbacca met Obi-Wan Kenobi, who was looking for passage to Alderaan. Chewie arranged a meeting between the rogue smuggler, the Jedi, and Luke Skywalker.
The first time, Obi-Wan tells Leia she reminds him of someone “fearless and stubborn,” a “leader who died a long time ago.” While it's possible he was referring to Satine Kryze (voiced by Anna Graves in the Clone Wars animated show), it seems more likely he was talking about Padme.
We know from Leia's parents and from moments in the Star Wars sequels that she was, in fact, Force-sensitive, even though she didn't get a chance to display those powers in the original trilogy.
Why does Obi-Wan Kenobi age like that? Because he's not real, and is a fictional character played by different people. You see, Obi-Wan Kenobi is played by Alec Guinness in the original trilogy. Guinness was 62 when he filmed A New Hope, and he died in 2000.
In A New Hope, Leia's utter faith in Obi-Wan Kenobi comes circuitously from her father, who, in that film, is never glimpsed. However, when Luke breaks Leia out of her cell and says, “I'm here with Ben Kenobi,” and Leia doesn't miss a beat. She knows that's his other name.
Obi-Wan Was Pretending He Didn't Know R2-D2
The base assumption of why Obi-Wan doesn't remember R2-D2 -- in light of the prequels -- is that Obi-Wan is feigning ignorance in A New Hope to downplay the importance of the droid's arrival.
R2-D2 was present when Padmé gave birth to Leia and Luke, so he knew Luke was Anakin's son – but what he didn't know was that Anakin became Darth Vader. In addition to that, Anakin's fall was surely a painful event in R2-D2's life, one that he definitely wouldn't like to remember or even talk about.
One would think plenty of people would vividly remember a war fought between faceless droid armies on one side and laser sword-wielding space wizards on the other. The explanation for this discrepancy has always been that the newly minted Emperor Palpatine went out of his way to bury all traces of the Jedi.
Vader's Quest takes place before Star Wars #35 and is specifically set two months after A New Hope, giving it the most specific answer to when Darth Vader learned that Luke Skywalker is his son in the Star Wars franchise.
The last time Kenobi and Vader saw each other before A New Hope chronologically, before Obi-Wan Kenobi that is, was Revenge of the Sith.
Nope. Luke, unlike Leia, never really had a father figure in the first place. Leia never was saved by Darth Vader the way Luke was, and never understood Luke's forgiving him. She hid her identity as Darth Vader's daughter, and identified as Bail Organa's daughter.
Even though he had a fierce confrontation with Leia Organa during the opening scenes of 'Star Wars Episode IV: A New Hope,' he never even suspected she was his daughter. That was why the only person Vader targeted and tried to convince to turn to the dark side was Luke, as he didn't even know that he had a sister.
The reason Leia likely remembers Padmé is that she could sense her mother's emotions at the time of the senator's passing. Luke didn't possess the same ability as his sister and inherited their father's Force potential. This links with Luke's desire to follow Anakin's Jedi path.
This is not because the Third Sister knows that Leia is Anakin Skywalker's child; it is because the Third Sister found a link between Obi-Wan and Bail Organa and she believed Obi-Wan would do anything to save Bail's daughter.
With Leia's strong connection to the Force, it seems like the most likely solution to this inconsistency is that she's caught glimpses of her mother through Force visions. As Luke trains with Yoda on Dagobah during Star Wars: The Empire Strikes Back, the wise old master says, "Through the Force, things you will see.