@JKTV
That is true.
Even though she likes Uta, she is blinded, probably by the crappy life full of lies, and she will have to chose to see.
@Oeconomist
Indeed we cannot know it for certain, we can only suspect, but the thing is: there are signs the Kaori likes Uta as a woman. For instance, she wants to be near Uta, you may love your parents, but you wouldn't want to be near them all the time, or how Uta's presence alone was enough that Kaori's mental breakdown had diminished effects, or how Kaori is always remembering Uta, in some way or another, almost in every situation, or how she shares her life with Uta without a thought.
We may be wrong, it's true, but the signs are there, almost every instance of these are meant to a girlfriend/boyfriend, not a sibling or a parent.