You may assume that theft and robbery are the same because it would get something that belongs to another person, but this time, you need to remember that there are some differences. When you say theft, this means that you are getting something from the person without potential intimidation. This means that someone who is thieving might get money or objects without the victim knowing about it immediately.
When someone is robbed, this means that the person had to undergo intimidation and force so that the property or the money can be forcibly taken from the other person. Robbery is considered to be a more serious crime because it is considered to be more violent than theft.