Mask (2015)

Seon Woo receives calla every morning and wants to find out who the secret admirer is. One day, he goes to a nearby florist’s where he meets Ji Hee. He falls in love with her at first sight, thinking she is the one who is sending him flowers. Seon Woo asks Ji Hee to go on a date, and she agrees. He arrives at the rendezvous only to find that Ji Hee is held hostage and, to his horror, killed before his eyes.

Main character also uses someone else identity due to complicated family issues.
She then falls in love and starts a relationship while hiding her true identity.
Mask is more about the lies and betrayal between the couple, their relationship is more complicated and not as stable as in Flower of Evil.

Rich main guy from a popular family
Poor main girl with a good heart
Switched bride marries the main guy
Couple falling in love gradually after marriage
Perfect couple has comedy while Mask is dark

Both are about a couple, which tries to survive the turmoils within their own family and circle of friends and save the family company. Both male leads have crazy sisters, which tries to sabotage their love lationship. Female leads are innocent people, which learns to lie even to their most loved one.

Tatsuya was killed in a car accident and his spirit lives in Hikata - the one who killed him in the accident. Since then, he had a hard time trying to change his girlfriend's perception of "him" or "Hikata" while still trying to protect her.

Both have female lead acting/believing they are someone else. The male lead acts offensive in the beginning in both dramas.

They both keep you at the edge of your seats and won't let you fall just yet. Also, you're always feeling apprehensive about what is going to happen next!