Male lead marries Female lead because of some business opportunity or something, but when he finds out that she is getting hurt because of his family, he helps her and slowly falls in love with her.

Can someone tell me name of the drama which has similar plot

Marriage without dating has a similar theme. The Main lead makes a deal with the girl so his mum will stop trying to make him get married. After their families interact they slowly start to fall for each other... unless you've watched it all ready. 

Encounter, a recent 2018 drama. This was more the backstory.

The fl married the 2ml way back when, but his family was toxic, so he divorced her for her own good. The marriage was arranged for political/business reasons. Fast forward a few years, the fl meets someone and is finally happy, then the 2ml realises he loves her, wants to get her back and fails miserably. 

Not quite the same, but very similar.

  • Bride of the century - ML is arranged to be married to a girl (not yet married), but the girl doesnt want to be engaged thus she gets a lookalike girl who is th FL. And so the ML and FL (fake fiancee') goes through the process of arranged marriage for business purpose. And they bivker yet slowly the hearts open up. But ML finds out that there is a curse in his family, that the first brides of the famiky ends up being killed at the eve of their wedding, so he tries to break up with FL. 

One of the couple of WWW Search. Though the falling in love part is a little questionable, though it is somewhat implied.

Whick k-drama is this? Any ideas?

A guy (I think celebrity) meets an ordinary girl by chance but people misunderstand that they are a couple so the guy ask the girl to pretend to be his girlfriend or something.  I think I only saw the trailor of this once and it's been a while so this is all I can remember. :/

Ah thank you. But its not korean drama right? I clearly remember it was korean drama.. Hmmm.. also I think the guy is some korean idol. And he holds the girl or hugs her by accident and paparazzi takes a pic and think they are dating so he gets in trouble.. 

Full House - though the reason they were seen as hugging but paparazzi is because the SFL who the ML likes, asks him, if she likes her. And since the question is born out of the SFL's frustration of being rejected a couple times by the SML who SFL likes. Plus they become "engaged" and married. Not just BF/GF. While smiling pasta, they get photographed and act like a loving GF/BF only.