would prefer...

[auster]

I would prefer you not to smoke.
Is it a wish or a resquest? to a native.

 

[isedehi]

I would prefer you not to smoke.
Is it a wish or a resquest? to a native.

'I'd rather you didn't smoke' or 'i would prefer you didn't smoke' is a better way of putting it. Im not a native so i wouldn't answer your 'wish or request' question. ( You specifically mentioned you wanted a native speaker to answer that)

 

[leonwool]

Context is the key. Even the tone of voice in speech can effect this.

"I wish you would not do that" sound like a firm request.