This is one of the most genuinely difficult things about international Catholic dating, and most people handle it badly in one of two directions. Either they dismiss real warning signs as cultural differences they don't understand yet - or they disqualify someone for something that is simply unfamiliar.
Here is the most useful test: is this rooted in their character, or in their upbringing?
Character issues look the same across cultures. Dishonesty looks the same. A pattern of deflecting responsibility looks the same. The way someone speaks about people they have no reason to impress - service staff, exes, family members they are in conflict with - that tells you who they are, regardless of where they grew up. A person who is unkind in their home culture does not become kind because they moved countries.
Cultural differences, on the other hand, are usually about expression rather than substance. How direct or indirect someone is. How much they involve family in decisions. How they show affection. These things are real and they matter and they will require genuine conversation and negotiation - but they are not the same as a character flaw.
The harder cases are where culture and character have been genuinely intertwined. Someone who grew up in an environment where emotional avoidance was normal may have built it into their personality. That is not purely cultural - but it is also not immovable. The question is whether they are aware of it and working on it, or whether they are using culture as a shield against having to grow.
Pay attention to how someone responds when you name something that concerns you. Do they engage with it honestly? Do they dismiss it or become defensive? That response tells you more than the original behaviour did.
Give people room to be different from you. But do not give so much room that you talk yourself out of what you are clearly seeing.
