"Good evening, dear!"
Translation:Bonan vesperon, kara!
Good point. I read once, that you have to repeat something 4,000 times before it is permanently implanted into your brain (think about driving a manual transmission car - after 4,000 gear shifts, you can drive without thinking about the clutch).
I suggest you walk around all day repeating vesperon, vesperon, vesperon...
The way I remember it is: in Catalan the word "evening" is "vespre" and "vesperon" is similar.
if you know any Russian, dobry vecher is good evening, many of the Slavic languages have a similar sound for evening when used in this context.
If you don't have any knowledge of Slavic languages, the ONLY word I can think of that rhymes with vesperon is Vespa (as in the motor scooter). Try to think, "He drives his Vespa scooter in the evening.
Not sure what the etiquette is for replying to old questions (2 years old at this time), but my sense is that there's an unspoken word in the practice sentence, like "...dear [friend | spouse | parent | teacher | whoever].", so kara (which ends in "a") would be an adjective applied to the (unspoken) noun (which would have ended in "o").