Leia does not seem to react to tragedy. Instead, she has this wonderful ability to stay perfectly alert, reasonable, and careful of the feelings of others. She witnessed the destruction of her entire planet, and still had the mental and emotional strength to escape with Luke and Obi-Wan.
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.
Theory 1: Leia Doesn't Remember Ben Is Obi-Wan
Throughout her encounters with Kenobi in the series, he refers to himself as Ben. 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.
The Inverse analysis — The new revelation that Leia was buddies with Obi-Wan when she was a kid isn't just some cool canon twist, it also adds a tragic layer to everything that happens in A New Hope. Leia doesn't get to reunite with Obi-Wan, and instead, just before escaping with Han and Luke, she sees his murder.
In Death Star, it seems the Sith Lord could have discovered Leia's true identity if he'd pursued his hunch. However, Leia's strong-mindedness during Vader's probe denied him the opportunity to discover she was his daughter.
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.
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.
Prior to this series, it never made a lot of sense why Leia would've named her son after Ben Kenobi, the mentor of her brother whom she never met.
While other factors (like her love for Han) kept Leia from becoming a Jedi, Darth Vader's evil existence was definitely a big part of it. Leia wanted to lead and reshape the galaxy, but wielding the same power that had corrupted Vader would be too big of a temptation because she would have become a powerful Jedi.
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.
While the events of Star Wars: Bloodline explain why Leia did not name her son after her biological father, Obi-Wan Kenobi makes Han and Leia's decision to name their son Ben far more understandable. In "Part I," mercenaries hired by the Third Sister, Reva, kidnap Leia to draw Obi-Wan out of hiding.
But when little Leia realized Obi-Wan had known her birth mother, he shared a story that not only made Leia's memories of Padmé plausible, it made them all the more moving. Jedi took babies from their families at an age when no child can retain memories.
For their heroism in destroying the Death Star, Han Solo and Luke Skywalker receive the Medal of Yavin from Leia Organa in a ceremony on Yavin 4. Decades later, Maz Kanata gives Chewbacca the medal once worn by Han, which Leia was holding when she died.
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.
It is revealed that it was all a plan made by Obi-Wan, Yoda and Mace Windu, who decided to fake Obi-Wan's death so he could pretend to become a member of a looming Separatist plot to kidnap Palpatine.
With Leia, Luke, and Darth Vader all being major characters in "Obi-Wan Kenboi," the show is having to tread lightly as the "Star Wars" canon is pretty explicit. We know exactly when Vader discovered that Luke was his son, and we know when he figured out that Leia was connected to him as well.
It's not just about the rescue. In episode two, Leia reminds Obi-Wan of someone "fearless and stubborn" that he used to know. Not a Jedi, but "a leader." Kenobi is of course talking about Padmé Amidala, Leia's biological mother, but she doesn't realise that at this point.
When Organa reminds him, “What about your duty to his sister?” Obi-Wan's mind changes, and he agrees to help. He finds and rescues the young Princess Leia, but their journey back to Alderaan is not an easy one. Throughout multiple narrow brushes with death, the two rely on each other for comfort and strength.
Leia Organa-Skywalker
Leia Amidala Skywalker (portrayed by Carrie Fisher) is the wife of Han Solo, the mother of Ben Solo, the younger twin sister of Luke Skywalker, the daughter of Anakin Skywalker and Padmé Amidala, and the granddaughter of Shmi Skywalker, raised by Bail and Breha Organa of Alderaan.
Vader discovers Leia is his daughter because of Luke.
Luke had only recently discovered the two were siblings and, even more recently, had revealed their connection to the princess. Vader likely sensed their emotional bond through the Force when speaking with his son.
Yes, when Darth Vader turned back to Anakin Skywalker and sacrifice himself to save his son, he dies and Obi-Wan uses the force to connect with Anakin's spirit. In that time Anakin apologizes to Obi-Wan, desperately asking him to forgive him for everything he has done to him and everybody over the years.
In Star Wars Legends Leia was visited by the force ghost of her father Anakin Skywalker, the man who used to be Darth Vader. It wasn't a pleasant meeting as Leia was unable to forgive him for the things he'd done no matter how hard he begged, and it was the only time she saw him.
Star Wars is finally exploring Leia's emotional reaction to the revelation Darth Vader was really her father - as her identity is transformed. Star Wars has finally revealed Princess Leia's reaction to learning Darth Vader was her father.