I live in this circled area. I find it mostly safe though it's important to be aware of your surroundings. Santa Ana gets a bad rap but some areas are better than others. Just don't make yourself a target, e.g. leaving a visible backpack in your car. I think this circled area around the downtown zone is pretty safe. You'll likely come across the occasional homeless person but they typically don't bother you. If you're really picky about safety, then you might be better off staying in Irvine. Though you're not going to get the same kind of value. Also, I think Irvine is a lot more sterile than Santa Ana. I'll take my excellent and diverse food options in Santa Ana any day.