My best friend is going to immigrate to America (the girl is only 20 years old). Should I persuade her or bless her? How can I persuade her and tell her that she is safe?

Now that you have made a decision, don't stop her development for personal reasons. Best wishes. Pay attention to safety or something I'm sure she'll pay attention herself. Mainly to express your regret for her, and your longing and expectation for her future. I hope she can get familiar with the living environment in America as soon as possible, and I hope she can live a life she likes in America. With feelings, you can also contact online, and you want to open up a little ~