NO she DID NOT help Mariam because her parents were forcing her to get married, she helped Mariam because her parents were forcing her to get married to the very same man who RAPED her!
Mr Khan now you cannot(and you should not)find an excuse to not to appreciate(or even adore) ZOYA's goodness!
Thoroughly remind yourself the words your mother told you,"Once ZOYA gets to know about somebody's sorrow, she does not stop until she makes that person happy" and accept the fact that you were wrong!
Going by the narrators dialogue in the promo," ZOYA ki himmat dekh kar, kya hoga ASAD ko ehsas uski chaahat ka?" we should not accept anything less than this!
And what were you telling ZOYA, Mr Khan that she should have informed you? Oh, really! Like you listen to her!
If she would have decided to inform you, her 10 minutes would have been lost in the attempts to make you listen! You would have gone by your legitimate ways and called the police, perhaps the very same policeman who instead of helping locked you and ZOYA up!
By all this time Mariam's parents would have succeded in making her say 'Qubool hai' and finding the very first moment of solitude Mariam would have attempted suicide! End of the story.
Just can't wait for the scene when after returning from Mangalpur, ASAD narrates the entire story to his mother and FINALLY accepts the fact that he has grossly misjudged her!