The British tend to distinguish "sick" from "ill" with "sick" meaning "nausea." Americans don't generally make such a distinction. Does this Vietnamese expression have a particular connotation?
I would say you will get sick meaning you are doing something that will lead to illness. On the other hand you will be sick means you are doing something e.g. reading in a vehicle that will induce you to vomit. What exactly does this mean in Vn?