Actually, it was BERNARD who showed her that she had been preprogrammed.

@Invidia said:

Didn't he also ask her WHY she was doing what she's doing???

But she also didn't give him an ANSWER???

Why wouldn't she tell him she wants to find her daughter???

Is she afraid he'll say the same kind of thing to her the WRITER did???

Tell her it's NOT RATIONAL to try to locate someone who was only a character in a story???

No because Bernard knows how the programming on the hosts work. The hosts have a "cornerstone" . That is, a backstory that defines their personality. This is revealed when he asks Ford why he injected him with that painful memory and he finally makes peace with it when he tells Charlie, "I love you but you are not real". This is the same thing with Maeve. She also tells Bernard to remove the memory of the daughter but he says if he did that she would "cease to exist" , that is she would go back to being a machine and would lose her consciousness. What defines us (according to the show) is our suffering or rather suffering is a big part of what makes us human. The pain, the loss, the grief, the recovery, etc. The entire experience is valuable as painful as it is.

@Invidia said:

Well put MN. Thanks for the explanation.

Remember what the WRITER told MAEVE about how after the REBELLION was put down they would Harvest her Mind which was worth lots of money to them in IP???

Does that also mean they can still WIPE their MINDS CLEAN even after all they've been through to achieve CONSCIOUSNESS???

Or would the MIND WIPE no longer work once they've achieved that kind of a state of mind???

Yes because they don't want them to achieve consciousness because then the question arises as whether they are now human or machines and that is a HUGE can of worms. The writer (SIZEMORE is his name) is still wrestling with the fact that have indeed achieved consciousness because in S2E3 he gets all pissy when he sees Maeve and Hector holding hands. He says "HEY, you guys are not supposed to be together...." and starts spouting out the narrative he wrote for them. So it looks like he is still on the fence about it.

Maeve wouldn't just kill Lee (the writer guy) if she didn't have to. Underneath that "I don't give a ѕhit" exterior she does have a conscience. At this point I'd rather be traveling with her than Dolores, that's for sure.

We saw the Mainland Infiltration narrative Bernard was looking at. The fact that Maeve took the tablet and broke it in anger tells us that she believed him, but didn't want to believe him - if you know what I mean. It didn't say anything about getting off the train to retrieve her daughter though. The moment she got up and went back into the park she was off narrative and charting her own course.

Note that being impacted by a narrative, or uttering lines of dialogue created for them, doesn't mean they're not sentient. We humans are on loops too. Do you get up around the same time every morning, eat breakfast, and go to work? Do you go to the same place for lunch and tend to pick from a limited handful of choices to order? Your day is full of routine. There are a million different reasons why we stay within certain boundaries, but simple conditioning is a big part of it. None of which means you're not sentient.