My theory after connecting all dots and few of my friends helped with some info
So akshu will be in those cloths due to some act. That cameon villain who is getting hyped he must have came for wedding and intoxicated a drink which akshu drank.
Then akshu will go to abhinav as she wanted to confess the truth. She says that she was waiting for right time. If it was navra confession then she had many opportunities to do that.
Jhula scene,
A day before abhi entered into sharma house
Their date
Time in goenka house.
As akshu is very expressive when she loved some one. So she don't need opportunity to say she loves some one.
This time she want to tell him she never moved on she still love abhimanyu. But she will try her best to love him but she needs time.
That's when abhimanyu hears it and she gets shocked and in their verbal argument akshu confesses that she loves him and which manju over hears.
Hence the promo and manju starts observing abhira post that scene and realizes that abhira are always meant for each other and she will verbally start showing it like in precap and abhinav over hears it and starts oberving abhir along with her.