欣欣的英文：
joyfully

Trees are growing in prosperity and springs are gushing without stopping.
木欣欣以向荣，泉涓涓而始流。

My own criterion of success is the ability to work joyfully.
我自己成功的标准是能够快乐地工作。

After the seminar, guests joyfully partake in a delicious, free vegetarian buffet.
讲座结束后，来宾们欢喜地享用美味素食餐点。