Here is my imaginative theory:
Heer, who has both the diary and the money will be caught by the police. The police will see her with the money, and eventually get hold of the diary with the help of the manager ( who seems to have a personal problem with Heer). At that time the only thing that will come out from Heer's mouth is "nahin.....main....woh.....ladki......." and then she will start weeping. (other kekta heroines, who says so much usually, becomes numb at such crisis period, so God knows what will happen to heer, who is already so silent.)
The Police will handcuff her and drag her to the police car and at that precise moment Prem will make an entry. But before he can gather as to what is happening the car will drive away. Prem will run behind the police car for a while (leaving his car) , then will stand still, confused and upset .
In the police station, Heer will be taken to the lock up. Prem will arrive and say that Heer is innocent. Prem will then say that he owns the hotel and whatever is going is his fault.....etc,etc. The police will bring out Heer and together they will go to the Hotel. There the Police will search Prem's cabin and will find the papers. Prem, who wants to save Heer but was equally confident about his innocence, will be shocked. Heer will be in a state of disbelief. Anyway, police will arrest Prem and Heer will say....'sir'. Getting the first chance, Prem will get hold of Heer's hand and will say that he will be fine.
At the news of Prem being arrested, Preet will hunt down the culprit and drop that guy on the police table, saying "yeh hai asli gunehgaar".
I think I have gone too far, so I will stop now.
Luv
Melissa