Only a year left but a stamped up service book from a main dealer and ideally any bills for wear and tear items replaced would inspire confidence.
Oh and check tyre tread levels, tyres are expensive and pretty well every car I have bought has needed new tyres. I don’t do driving on nearly bald...
I have had reasonable results from buying privately but yes it is a risk.
First impressions of the seller are a starting point.
Make sure the engine is not warm, walk away if it’s not cold
Check oil level and colour. As long as it’s not a diesel, the lighter the better. Ask when the last oil...