"越来越欣欣向荣" can be translated into English as "increasingly prosperous and thriving" or "more and more flourishing".
Both expressions convey the idea of continuous growth, vitality, and prosperity, aligning well with the original Chinese phrase. For example:
The economy is becoming increasingly prosperous and thriving.
（经济越来越欣欣向荣。）
The region is developing more and more flourishing with each passing year.
（这个地区一年比一年更加欣欣向荣。）