I ask because I got offered to buy it.
So these are only pics I got.
I dunno what to do now, guy says batteries are in good condition.
If someone has offered to sell you it then they should be telling you what make and model the bike is, what year it was made, how much use it has had etc.
I guess that the owner hasn't told you anything about it or you wouldn't be asking?
How much are they asking for it?
Of course it is totally up to you but it looks to be a very cheaply made bike:
Cup & cone bottom bracket (nothing wrong with this - simply older technology that only tends to be used on cheap bikes these days)
Front disc brake and rear v brake (weird to have both - again, only ever seen this on cheap bikes).
As other have mentioned, it hasn't been built right so I doubt the owner knows enough to have maintained it mechanically.
Photo is quite blurry but looks like chainring teeth are sharply pointed which if this is the case would need replaced (probably along with a new chain and cassette/freewheel). As the chain wears it will wear down the cassette/freewheel, if you don't change it in time it will also wear down the chainrings till the are sharply pointed/sharktoothed. Good bikes allow you to fit a new chainring. Cheaper bikes have a sealed unit and you need to source a whole new crankset.
Personally if I was buying an electric bike I would buy one from a well known brand and check that you will be able to source spare batteries etc if/when things goes wrong.
Cheap bikes don't tend to be built for longevity and finding spares for a cheap bike may be an issue.