I think there are two fundamentally different types of "trust" being described in those writings and conversations, and it can confuse the audience enough that it's worth separating them.
The first kind of trust is a feeling of security -- you trust your neighbors, in the sense that you don't believe they're likely to do you harm, steal your stuff, spread nasty gossip about you, etc. Other people might do those things, but not your neighbors. You trust them. Or, if you don't trust your neighbors, it's because you believe they're likely to harm you in any of those ways.
The second kind is more about behavior than belief -- you show charity toward someone because you trust them, in the sense that you might have reasons to be suspicious, but you're setting aside those reasons, and giving them the benefit of the doubt.
Say one of your friends has a tendency to break small promises about 1/4 of the time, and now is the first time that the promise is a big one, so you can't judge based on an equivalent case in the past. If you trust him to keep his word in this unfamiliar case, you're acknowledging the risk but setting it aside (not denying that the risk actually exists). If you don't trust him, you can't bring yourself to give him the benefit of the doubt.
A sub-class of this second type is hospitality -- you always have reasons to be wary of guests you're hosting because they could take advantage of your letting your guard down. Ditto for the guest -- they always have reasons to be suspicious that their host could have ulterior motives for acting so generous. But the guest and host are putting those reasons aside, and trusting each other.
Putting aside these risks is not naive -- you recognize that they're there, but you are showing your faith that they won't blow up in this case.
Charity, hospitality, faith, compassion, mercy, forgiveness -- you get the idea of what this second kind of trust is about. Security, comfort, ease of mind, carrying on worry-free -- that's what the first kind of trust is about.
You read a lot about how the Nordic and Scandinavian countries are "high trust," but I think it must be in the sense of security and comfort. One Swede, surrounded by a lot of other Swedes, feels safe from possible harm or wrongdoing.
But what about charity and hospitality? My favorite example of hospitality in the modern world is hitch-hiking -- that's a solid example that no one will dispute as being a guest-host relationship. And you have to have pretty high trust (in the second sense) to pull it off. Otherwise, the driver thinks that the hitch-hiker might try to rob or kill them. Or the would-be hitch-hiker decides against asking for a ride because he assumes that the drivers will hit him up for money, take him hostage, kill him, or whatever.
Fortunately there's a website, Hitchwiki, that provides information to travelers about how easy or difficult it is to hitch-hike around the world. Each country has their own entry.
No strong consensus comes up for Finland. How about the liberal utopia just to the west? "Many say that hitching in Sweden sucks." Also: "Norway is not an easy country to hitch in ... Like in Sweden, foreign tourists and immigrants are more likely to pick up hitchhikers." Denmark is the only country that sounds close to Britain or America: "Most drivers are very friendly and hospitable." From my limited experience, I buy the idea that Danes are more extraverted and hospitable than Swedes or Norwegians. No clue about Finns, though.
It may not be impossible to rely on the hospitality of strangers in Scandinavia, but it sure sounds more difficult than in other Western countries. The entries for Norway and Sweden are defensive, trying to convince you that it's not hopeless, and again that most of the host drivers will not be native Scandinavians.
On the discussion page for Norway, there's a good explanation of why hospitality is not very strong in socialist Scandinavia:
...the very good welfare system in scandinavia. People are not used to help each other, because the goverment takes care and there is no need for solidarity (even the homeless in stockholm have a mobile haha) to each other.
Hospitality is a face-to-face, approaching form of trust. Scandinavians don't want unfortunate people standing on the side of the road waiting for a ride -- but they think the solution should come from the government, not from the everyday driver. This is distancing and avoidant -- outsource the job to a remote group like a bureaucracy, and the problem will be solved without the average citizen having to take part personally.
By the way, I don't think that state involvement erodes hospitality, but the other way around -- people who are uncomfortable providing hospitality find an alternate solution, creating a state bureaucracy to handle the job instead.
You see this in Sweden even more clearly with their immigration problem. They don't have a general fear of foreigners, or they wouldn't let so many in. Rather, they are OK with them arriving -- as long as they can be handed over to government workers to be taken care of. Letting a foreigner into the country who will be supported by the welfare system -- OK. Picking up a foreign hitch-hiker -- no way.
What countries do show high trust in the form of hospitality?
Iran is a very friendly country. [...] Finding a place to sleep in Iran is generally as easy as knocking the first door you come across. If you get tired of the unrelenting hospitality however, the city parks offer an excellent alternative. Many parks, even in big cities, are designated as camping zones, with toilets open all night. Camp fires are tolerated, but it's best to ask before.
Turkey is an extremely hitchhiking-friendly country. [...] You will never have to worry about lack of food in Turkey. Many truck drivers have coffee makers in their truck. Turkish people are very generous, and it is rare that you will get a lift without a driver offering you food. ... The tea (black tea or apple tea in Istanbul) is the national drink, and almost all the people that you meet offer you a tea − this is probably the most common way of showing you their hospitable culture.
The flip-side to the "culture of honor" is the culture of hospitality. You do unto others as they do unto you, though starting off with a caring gesture. If it continues, you're in the hospitality side of their culture. If you show them disrespect, you've started a possible feud, and are now in the honor-based side of their culture. Both of these seemingly different treatments are in fact the same -- an obsession with reciprocation, face-to-face.
Cultures of honor (and hospitality) are most common among pastoralist people, most famously around the Mediterranean and through the Middle East. Cultures of law (and order) are found more among sedentary agrarian farmers, with East Asia being the best example. Western Europe reflects both traditions because its people come from agro-pastoralist stock.
The two cultures have different ways of helping out a stranded stranger -- the one in a more personal, hospitable way, and the other in a more distancing and bureaucratic way. Evidently, these two approaches create two different forms of trust -- one where average people give the stranger the benefit of the doubt, and the other where they outsource it to third parties and rest safe and secure knowing that someone else is taking care of the problem.