gazelle. my darling. my beloved. got so angry when one evil rich man tried to get her to kill people for him only to end up agreeing to do exactly that for another possibly eviler rich man.
the circumstances differ, obvi. leopold leveraged gazelle's gratitude towards him against her (while subtly threatening the safety of her family too), while valentine was essentially just like 'if you don't want to kill people it's fine, i can just hire someone else to do it lol'.
the illusion of choice... bc there's no way valentine would've kept her around if she actually said no. and gazelle knows that, but the fact that it's presented like a choice is important. at least valentine is willing to pretend she has some agency. and by the time he makes the offer, she's already made her first kill, so it's easy to say yes.
she was so up in arms about leopold telling her to kill other people for him, but she has no problem at all killing him. so clearly it wasn't so much the murder that was the issue for her as much as it was the idea of being forced into it.
that said, she's not unaware that valentine, like leopold, is just using her as a weapon. she's just also aware she essentially has no other avenues left. there were two witnesses to leopold's murder, and if they weren't working together then there was no reason to keep gazelle around.
i do think the dynamic she has w/ valentine in the movie is still real. they have their fun. she teases him about how squeamish he is. he treats her more like a confidant than an employee. it's just shallower than it seems. he has use for her sure but he doesn't respect her any more than leopold ever did. and for all that she laughs around him, gazelle doesn't actually like valentine.
morally, she's kinda a mixed bag. worse in some ways bc she doesn't really have principles..... she's not working for valentine because she sees his vision or cares about his justifications in what he's doing. she's just along for the ride. but better in the sense that she would not inflict any large scale damage on her own (just lots of small scale damage... all the time). fact is, she revels in being dangerous. some of it stems from having been looked down on and consistently underestimated in life, but a lot of it just boils down to the fact that she likes it. it feels good to know she's the sharpest weapon in the room. and if she can't find a reason of her own to point her blades whenever and wherever she likes, then she'll borrow someone else's.
u might look at all that and think. okay so she doesn't really care about other people. and that's mostly true, but she does genuinely love her family. it's just... the second leopold threatened their safety to coerce her into doing his bidding, gazelle got the ick a little bit :/. she loves them! but it's annoying how they've become a weakness, her achilles' heel if you will. it's not their fault, she knows that, and she still does talk to her sister pretty often, but she keeps her physical distance, especially with her parents. they don't really understand, and are quite heartbroken by it. gazelle gets hit by the 'don't call my parents enough' guilt ever so often, but things were just never the same ever since she got the ick/realised they were a liability</3.
so she is capable of love and warmth, it's just... maybe don't expect it to last very long. or to look very nice.