Absolutely agree that it was because of Abhi's words on the terrace that Simi built the courage in her to go and talk to her father.
Thats where Abhi fills in the remaining 25% confidence in Simi's already existing 75%.
And thats how in my view Abhi completes Simi.
Like in Abhi's own words, "the way he knows her and understands her, nobody would". That is a supreme confidence and Simi is 100% lucky to have Abhi and I am happy for her. He would pull her out from any situation,provided she lets him to.
Similarly, it is necessary that Simi also should complete Abhi for a love to be complete from both sides.
It is yet to be seen how it is shown by Simi, and not just that, that 'Abhi is childish and Simi is mature so they complete each other'. They really need to show something concrete, starting from why Abhi fell for Simi.