There is no warranty of sorts if the bike has an issue within 30 days with the safety. If there is something blatently wrong, and the bike has a safety, you can contact the Ministry of Transporation and/or the shop that wrote the safety to have it addressed, but there might be a cost to make the necessary repair, so be prepared for that. There is no recourse to the seller.
Getting delivery to your home with the bike for free, or for cheap is a MASSIVE plus. A minor cost is very acceptable, most sellers are not willing to deliver - thats your arrangment you have to normally make.
If you do not know what you are looking for in a bike, or WHAT to look for in a private or dealer sold bike, take someone who knows what the are doing, and not that guy you met at the Tim Hortons wearing the flip flops on his chromed out Gixxer - he probably knows less than you do!
Lastly, regard this particular bike you were looking at - I would NOT buy this bike. The 'minor' rust on the chain is the key indicator.
1) The seller could not take the little time to properly prepare the bike for sale
2) The seller could not be bothered to do VERY BASIC maintenance to clean and lubricate the chain with proper chain lube - hense there is RUST on the chain, where there should be none.
3) The bike likely did not visit a dealer or proper technician for some period of time - a proper tech would clean and lube the chain, hense, no rust
4) If the chain hasn't been properly serviced, which is very easy to do, what else was not done on schedule or properly?
If I was a buyer of this bike, I would have walked away from this bike the second I saw the rusty chain - it's that telling.
A verbal agreement to buy and a handshake is "technically" an agreement to purchase, but without a payment made or deposit (what is called 'consideration') there is no strength to the agreement to be upheld from either side. In the case of a motorvehicle sale, a bill of sale comes with the UVIP - there is no reason to not complete the bill of sale, and make a proper contract of the sale agreement. As such, you reasonably can back out of the sale as no deposit was made, nor a contract signed. However, it is mature and proper to call the seller to advise of a lack of further interest in their bike to be polite.