"It wouldn't surprise me if he is older than he appears".

[MeyaN]

"It wouldn't surprise me if he is older than he appears".

'Wouldn't' must be replaced with won't, right? Or is the above sentence okay?

Thank you.

 

[Raymott]

The original is OK. It depends on your meaning. "It won't surprise me" implies that you are going to find out.
"It wouldn't surprise me" implies that if you did find out (which is not certain), you wouldn't be surprised.

 

[MeyaN]

Would, and is and appears in the same sentence sounded little unnatural. Thanks for the clarification.

Could you please give me some more examples of 'grammatically-unnatural-sounding' sentences with would.

Grammar books don't have such examples. Hence, the request.

Thank you.

 

[Rover_KE]

As Raymott said, your title sentence is OK.

Like grammar book writers, most of us don't find it a good use of our time to compose unnatural-sounding sentences.

Just ask us about any you encounter which sound dodgy to you.