Mina Y. answered 07/12/20
Master of SLP, Certified Korean language educator+20, Korean professor
Thank you for showing your interest to my question!
The right expression could be
1. “안전하고 건강하길 (바래)!” if the listener is your friend or
2.“안전하고 건강하시길 (바래요)” if the listener is older than you.
Let’s analyze these expressions.
- 안전(safe) + 하고 (and) + 건강하(healthy) + 길 (short form of 기를)! 바래 (hope)
길 = 기를 = 기 (noun phrase mark) + 를 (object mark)
2.시 (respectful mark)
You might have a couple of more questions about this expression above. Let me explain deeply for you below.
1. About “를”
As you know, “Stay safe and health!” is not a full sentence in English. The full sentence can be “I hope you stay safe and healthy!”, right? By the way, do you what the object is in this sentence?? In other word, what do you "hope" for in this sentence? The object should be “you stay safe and healthy” grammatically.
In Korean, normally, you put the object mark ‘을/를’(depending of previous sounds), to clarify that the word or phrase is object. For example, if you want to say “I like apple” in Korean, you can say “난 사과를 좋아해.”
난 (I) + 사과(apple) 를 (object mark) + 좋아해 (verb).
2. About “시”
As you might know or not, Korean has “respectful mark” according to listener’s age, status or relational closeness between talkers.
Basically, Korean people honor especially seniors, teachers, professors etc. So their language has specific way to express honor those people by adding "respectful mark". So if you want to say “stay safe and healthy!” to your professor, you need to add a respectful mark “시” and “요” to adjective and verbs.
Now, let’s see the respectful expression (number 2 sentence) again here.
“안전하고 건강하시길 바래요!”
Let's analyze it.
안전(safe) + 하고(and) + 건강하(healthy) + 시 (respectful mark) + 길( noun phrase mark & object mark) + 바래 (hope) + 요(respectful ending)!
Does it make sense to you? I really hope so.
If you have any questions, please let me know! Thanks and have a great day!
안전하고 건강하길 바래요!
Best,
Mina Yeon
p.s ) Sometimes, speaker would like to honor audience. So speaker can put "respectful marks" when they speak to his/her audience. That's why I put the "respectful marks" on my last sentence for you. :)

Mina Y.
07/13/20