Iran is one of the most hospitable countries in the world, he says, promising that if I interviewed 100 New Zealanders who visited it last year, every one of them would have come back happy.
"If one of them, a single one, was unhappy, I am ready to accept everything. We respect foreigners, friends. Everybody tries to help you."
There is more than affection when he speaks about New Zealand: when it comes to the Christchurch earthquake, it is more a case of empathy.
Earthquakes in Iran killed 50,000 people in 1990 and nearly as many in 2003.
As soon as the Christchurch earthquake happened, he asked his staff to donate blood, and led by example.
"I have donated four times up to now," he says. "We are human. If an earthquake happened in Christchurch or Tehran we are human here, we should support each other."
The conversation becomes more fevered when it comes to immediate matters - claims that Iran's nuclear energy programme is expanding into weapons capability, the "demonisation" of Iran, and this week's major developments.
Tafreshi becomes very defensive.
"Iran is not going to attack any country. We are a defensive country. We need security in our region. We need peace. We need money. We need tourists.
"But of course we want to be independent. We want to be calculated. We don't want to be demonised by others. We would like to defend what our predecessors as a great nation left for us."
Iran is top of the agenda in Washington, he says. United States President Barack Obama has warned there has been "too much loose talk of war" against Iran which could undermine diplomatic efforts.
But more importantly for Israeli Prime Minister Benjamin Netanyahu, who has talked of attacking Iranian nuclear sites, Obama has not ruled out supporting a military strike on Iran. "When it comes to preventing Iran from obtaining a nuclear weapon, I will take no options off the table."
On the diplomatic front, there has been a major development as well with six world powers (the five permanent members of the United Nations Security Council - China, Russia, the United States, France and Britain - plus Germany) agreeing to enter talks with Iran on its nuclear programme.
Iran has also agreed to give the UN watchdog the International Atomic Energy Agency conditional access to the Parchin military site, to which it was denied access for inspection in January and last month.
"Iran is always ready for dialogue," says Tafreshi. His defence of the previous inspection refusal is that the IAEA's previous visits were for talks only and that it showed no respect to the host country to just demand an inspection.
Tafreshi says Iran has a strong record of being peaceful and is being unfairly singled out for its uranium enrichment programme.
"More than 40 countries in the world could enrich uranium, such as Argentina, Brazil, Japan, Germany, Australia and Italy. Why not we? This excuse is not acceptable for a great nation. We didn't attack any country in the last 200 years. We have a very good record."
Much of the rest of the world does not share his optimism that the future under hardline conservative leadership such as that of President Ahmadinejad will automatically reflect the past.
And there is bound to be scepticism about whether the new round of talks will achieve anything or just add to the pile of promises, threats, sanctions and inspections that have accumulated steadily since 2005.
New Zealand plays an active role at the IAEA, based in Vienna, and has served on its board of governors. The bilateral relationship has been relatively long.
New Zealand established its embassy in Tehran in 1975, its first mission in the Middle East. It was in an era when Wellington was opposing French nuclear testing in the Pacific and four years before the Islamic revolution overthrew the monarchy and created the Islamic Republic of Iran. The crisis led to oil shortages that forced car-less days in New Zealand.
Tafreshi is mainly complimentary about New Zealand but questions why it backed the Security Council resolutions against Iran in 2006 "as an imminent threat", and yet nothing had happened. No country was attacked, no bomb produced and yet Iran was seen as a threat. "Why were you all so hasty in misusing the Security Council resolutions?"
New Zealand could play a stronger role, a more "justice and logic oriented role" in the Middle East, he believes. He says New Zealanders are honest and nice people.
That is a good basis for New Zealand having a bigger role especially in an era where logic holds sway.
"We are in the era of logic and those countries who can produce more logic can prevail better.
"From this point of view, New Zealand's capacity is not less [than] many European countries.
"You put some logic on the table. This logic will penetrate much more than the missile and much more than the weapons of mass destruction."
He calls after the interview to add that the US is simply trying to promote instability in order to justify its presence in the oil-rich region.
Iran opened its embassy in Wellington in the mid-1980s.
The relationship between New Zealand and Iran has been more friendly than that of diplomatic buddies such as Australia and Europe through the nuclear crises. Sanctions undertaken by New Zealand have been only those of the UN Security Council.
Last year, Australia imposed its own sanctions, joining countries such as the US and European nations in pursuing their own sanctions.
Wellington tells New Zealand companies they must register with the Ministry of Foreign Affairs and Trade before doing business in Iran.
New Zealand's position on Iran has been toughened slightly under Foreign Minister Murray McCully.
He has deferred the regular talks held under the auspices of the Political and Economic Co-operation Commission.
McCully won't comment on the possibility of a military strike against Iran's nuclear facilities in the event of nuclear-weapons capability being verified by the IAEA.
"What I can say is that we believe in the power of collective action and that has been a historical stance we have taken. So if there was to be something established in the IAEA, then we would engage with our partners in that organisation on what the next steps should be.
"We would form a view with others rather than forming an independent view."
He accepted that this was an era in which logic should play a part.
"And logic tells us that Iran needs to get around the table and do some explaining to the P5 [permanent five on the Security Council] plus one discussion that appears imminent is very welcome."
As to whether New Zealand believes Iran's assurances that its nuclear programme is for energy purposes only, McCully tells the Weekend Herald: "We always accept statements made at face value until we have reason to doubt them."