Does divorce occur if the wife is treated kindly after the husband swore, "Divorce by three upon you if you do not stop this talk, for you will see from me treatment you have never seen before," knowing that the husband only intended to threaten at that moment?

If you break this oath, your wife will be divorced irrevocably by triple talaq (definition), and this is the relied-upon opinion. Some scholars, like Ibn Taymiyyah, hold the view that this oath, which is not intended to effect divorce but rather for threat and emphasis, does not result in divorce upon breaking it; instead, you are required to offer an expiation for an oath (kaffarat yamin (definition)). The occurrence of breaking the oath depends on your intention behind what you uttered, so you are only absolved by the actualization of what you intended with your oath. We advise you to present the matter to trustworthy scholars in your country.