Kekkon Dekinai Otoko is the original Japanese version of The Man Who Can't Get Married. If you enjoyed one, you will probably enjoy the other!
Main protagonists are from different genders, but both are strange people who can't express themself well, while being a bit too blunt (or even considered rude) with others. Both of them make comfort with selling houses (although one of them is also an architect and the other is a seller). Both are found somewhat attractive, yet hard to approach and are considered probably hardly to get married... Yet many people pursue them.