Based on my prior knowledge, the number of persons a car can carry may impact the decision to buy the car. Let's analyze the relationship between the feature "persons" and the target variable "decision to buy this car".

If the capacity to carry persons is very limited (i.e., only 2 persons), it might be considered unacceptable or less desirable for some buyers. On the other hand, if the capacity is larger (4 or more persons), it might be seen as more suitable for families or for those looking for a car with more seating options.

Based on this analysis, let's create the dictionary:

```json
{
   "unacceptable": ["2"],
   "acceptable": ["2", "4"],
   "very good": ["4", "more"],
   "good": ["4"]
}
```

This dictionary reflects the possible values of the feature "persons" for each target class. Note that I have included the values that are most likely to be associated with the target classes, but have excluded values that are hard to predict or might not have a significant impact on the decision to buy the car.