Diana was very nervous; she knew the image Alita has of her and that put her in a disadvantageous position from the start but what else can she do?
If she could choose, she would have picked someone else to fall in love with and not Alita of all people. The more she ignored her and didn't even put her in her eyes, then she found herself falling for the other deeper.
She knew that she was doomed and she tried her best to ignore these feelings but months of not seeing Alita drove her crazy and she accepted it, that somehow, she had unknowingly fallen in love with the other.
Since it was already like this then it can only make sense if she joins her beloved one but the reality was simply too ugly and parading herself in front of Alita was simply impossible.
But after causing a scene at home for months, they finally agreed, and here there were.