By far the most english-speaking country in Asia (after singapore). You wouldn't have issue to communicate with people, have a normal daily life. Might have issue to communicate with the old generation, but most of the people will go out their way to help you. Mandarin is the official language, but they are now making a huge push to become a bilingual language[1]
For safety, from 0 to 10, I'd give it a 9.5. I like to joke about the daily biggest national news being a grandma who lost its cat, since not much "bad things" happens here. Most of the thing I lost were returned, for example I thought I've lost my bag with my ipad few years ago in a bar, but someone returned it the day after x)
https://www.taipeitimes.com/News/front/archives/2020/06/13/2...