Dragomira could just be denying herself, or being her usual cold self to keep up appearances with MC. It's subtle but she does seem to have some manner of concern for MC outside of her position as a professor.
She could be concerned about him in this way because hes a piece of the man she loves and couldnt have, so she doesnt want to see him get hurt and doesnt want to disappoint (or wants to impress) MCs dad.
I think Dragomira will need some major development to make the players really believe she sees MC as THE ONE without a doubt, because considering all the
huge time shes stuck with this rejection and dealing with the fact she couldnt have the only man she really wanted, will be really difficult to not link anything she does with or for MC, to MCs dad.
Even if MCs dad wanted to be with her now, and she refuses him to be with MC, a lot of players could see it as payback for the rejection and not real love for MC for example...and this payback would fit her character a lot.
If she says shes over it and now wants MC i dont think it would make much sense, how she would get over it in a flip of a coin when she got stuck on the thought of his dad for sooooo many years? The only answer would be because MC is the son...would not feel like real feelings for me.
If she says thats because MC accepted her unlike his father did this would not make sense either, i bet many men wanted to be with her this whole time but she never wanted any of them for obvious reasons...so why would be different with MC? Again, because he's the son, would not feel like real love.
If she says something on the line "what im feeling for you, i never felt for your dad" or "you were the only one who made me forget your dad" would not be good too imo, because would link her current feelings to the thought of MCs dad, and it would not give a reason for what shes feeling...it would feel like empty words.
If she sacrifices or risks herself for MC on the imminent fight or in any dangerous situation for example, again, could be a last sacrifice for the son of the man she loves, in other words, a sacrifice for the man she really loves, a.k.a MCs dad.