There are a few ways to determine if someone is real on Hangouts. The most obvious way is to look at their profile picture. If the person's photo looks like it was taken recently, then they're probably real. Additionally, if the person is responding to your messages and they seem to be genuinely interested in talking to you, then they're probably real. However, there's no 100% guarantee that someone is real on Hangouts, so always proceed with caution.