@lilylah As someone who has watched him grow up and knows him better than anyone, shouldn't she at least acknowledge that he likes her? I think that isn't the case, instead, I think she is aware of it, BUT she consciously decided to ignore his advances.
If she didn't realise it already, she would be incredibly dumb. Think about it. She constantly studied his behaviour and consistently analysed it from an onlooker's point of view, waiting to see what pushed him towards the downwards spiral that was the ending of the novel. As someone who always examines him, she knows him best. Yet she called him childish without further analysis. That could make her a daft researcher.
But I don't think she's that naive. In this chapter she considered being Alejandro's partner but decided she's not suitable. She just took the thought quickly without the slightest hint of alarm, which probably means it crossed her mind before. As a good researcher, she realised it, but as a jerk she still led him on anyways.
She never ever uses tact with Alejandro. I don't get why she couldn't burst his bubble earlier to avoid further complications. I think she's just not very nice. Or maybe she's dumb in the end for not doing anything about it.