Female lead is in forced arranged marriage with guy. She loves the male lead though. The guy she's betrothed to tries to make her fall for him, but doesn't work. Male and female leads end up together.

I immediately thought of Mary Stayed Out All Night
@Sara

Seen it, but thanks.
Marriage, Not Dating
Attention, Love

it's currently airing. It talked about them being in an arranged marriage (It was the grandpa's last wish or something) but I'm not sure how serious it is taken. One sided love from the female lead currently. Definitely worth checking out :)

Also Goong, I dropped it as it was too cliché for me but it does fit with what you're looking for.
@XingBack

Seen it.

@MacaroniHair

Attention, Love - Yeah, I'm looking for ones where she's arranged to be married to someone else. Not the main guy.

Goong - How much is like the manhwa? Because I've read that.
Another Miss Oh: she's already engaged to someone, it's not arranged, but she gets out of it and falls in love with the male lead. Then the guy she was engaged to comes back and tries to get her back. 
Not exactly what you were looking for, but it's pretty close. 
@kayleigh - I'll check it out.