I guess the “purpose” of marriage is to generate the next generation, but it makes the process a whole lot more tolerable if the two partner actualy like each other and get along with one another.
Knowing the persons middos (and picking someone with middos that match yours) should in theory make for a good marraige.
Besides, the Bobover Rebbe was quoted as saying, “people look for 6 things in a shidduch. 3 are irrelevant, 3 are indespensible.
The 3 that are irrelevant are money,looks and yichus; the 3 that are indespensable are middos, middos and middos”.
So I guess middos are up there on the checklist.