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human
[Star Wars] What did Owen and Beru Lars *really* know about Anakin?

So, in Ep IV, Beru seems to _happily_ reminisce when she states that Luke "has too much of his father in him". Which means she's either she's a psycho, or that she doesn't know about Darth Vader. 

Owen says "that's what I'm afraid of", which might imply that he _does_ know about Vader, but the point of the conversation seems to be that Luke isn't cut out for the quiet life of a Moisture Farmer on Tatooine.

The prequels raise the question of what are they reminiscing about/making an analogy to? Young Anakin wasn't really given the choice of a quiet life a a farmer; he went straight from slave to Jedi-trainee and left the planet before he even hit puberty. Which was also all before the Lars's entered the picture.

All you get from the prequels is that Owen and Beru met the guy once (with Beru saying nothing more than 'hello'), and _that_ visit ended with him slaughtering a whole village of Sand people. Which you think wouldn't leave much to reminisce over, or a very positive first impression. So the reaction is still weird. 

Perhaps they didn't know about the massacre? He could've have told his stepfather Cliegg that he'd saved/met Shmi and left out the gruesome bits. But on the other hand, Tatooine is supposedly a small planet where not much happens. So you'd think word would get 'round.

TL;DR: They act very weird talking about a person they only met once and who they have reason to know massacred women and children, and whom they might know is Darth Vader.
gpt
Beru and Owen don't know that Anakin is Vader at all. What they're afraid of is that Luke will go off, become a space hero, and get killed. Despite Owen's chiding of the boy, he loves him like a son. Owen doesn't want him to get hurt. Neither does Beru.