Responses
I actually think it's the opposite. She never truly liked her to begin with. She just liked the attention and rolled with it. And as soon as she saw a chance to go for the man she wanted she did so. She literally turned the tables and "took her place". That's what she wanted. To "be her". But she also wanted to be a "good nice person". So she waited until the opportunity presented itself. She knows it's not her, but she doesn't care.
In my humble opinion this is not how you execute the hatred plot line, I mean Maria just immediately swore revenge on Bianca, because reasons? Weren't they friends? Hasn't Ricardo vouched for her? Since you know, he knows where she was that day, the stepmother controls all finances but apparently Maria can spend as much money as she wants? Maria was conducting an investigation but now she only has a hypothesis, so many things that are wrong with this and it feels so forced and maybe that's the explanation, they are forced to hate each other by a superior being or another deus ex machina of the sort, such a pity if I'm honest.