“Do you share the same primary values?” I asked a young person who had approached me for advice about marriage. “For example, are you both Christians from the same denomination?”
The young person assured me that they did and that they were. This sounded satisfactory although I must admit that this does not always matter. (In this case it would, though.) If you take a nominal Catholic whose real core values are vegetarianism and earning money and a nominal Presbyterian whose real core values are also vegetarianism and earning money, then there is less likely to be marital friction and disappointment, however their devout or orange sash-wearing parents may feel about it.
It feels a bit risqué to encourage nominal Catholics to just admit to themselves that their faith is not really a core value and to look for fellow adherents to their real religion (money, animals, Gaia) when seeking a marriage partner. I will make up for this by pointing out that religious Catholics are often much more interested in actual marriage than nominal Christians are. Of course, it is extremely unfair for marriage-minded nominal Christians to go seeking spouses amongst devout Christians–unless, of course, they have an inner voice telling them that they really need to do that.