Why is this trope still a thing? There's only two ways an arranged marriage ends in manga & light novels:
1. The heroine actually does get married to mr Whoever Whatshisface, fanbase is outraged, series dies.
2. The heroine doesn't get married, and the experience strengthens the bond between her and the protagonist. However in the meanwhile, readers get bored of an overused cliche that only serves the role of a filler.
Just stop. It's dead already. Put it out of it's misery.