Depending on your business needs/wants, I have a couple ideas that may help you with this. There is no definitive way to handle this programmatically - especially if you need to consider international addresses, etc.
First solution is to have a conditional that looks first to see if there is a space inside the string and then verifies if the length of the substring after the space is greater then 4 (arbitrary number I added to verify its a real address and not just an apt letter or similar - can change based on your use case).
WHERE CHARINDEX(' ', address) > 0 AND LEN(RIGHT(address,LEN(address) - CHARINDEX(' ', address))) > 4
The other solution is to check how many spaces are inside the string. For instance, it would need at least 2 spaces for it to be a real address. E.g.
121B Baker Street has 2 spaces, where
121 Street only has one. The one consideration is if they do not have a house number, but only a street name e.g.
Baker Street of the input is incorrect e.g.
121B BakerStreet then it will fall off.
WHERE LEN(address) - LEN(REPLACE(address, ' ', '')) > 1
I find the above two to be the simplest and most universal options around this. There are other options, but they are more niche and require specific business rules on input data or data formation, so I won't go into them here.