Good fit vs. Best fit - Lower end of the fit range (Difference of 1 cm). Is it OK? or can this tiny difference still cause pains? I want to buy a second hand Trek Cronus (Gary Fischer Collection) bike (50cms) for my wife. I am getting a good deal on it. My wife's height is 156cms. As per the Trek Sizing chart, the range of rider height for a 50cms bike is from 157cms to 165cms. So technically the perfect fit for 50cms looks like 161cms. 

So, my query is that would a 1 cm difference (her height of 156cms vs fit starting from 157cms) matter in causing any kind of pains (knee, back etc.) for her in the long run for her? I would ideally like her to go for her perfect fit of 47cms Trek bike. However, this second hand carbon fiber bike with Shimano 105 components is priced at the same rate as a new Trek One series 1.1 with a Shimano Claris components. That's the main pull.

Also, on a side note, how is the Trek Cronus (Gary Fischer Collection) bike? I tried to read reviews. But I did not find many for this particular model as I found for the regular Domanes, Emondas etc.

I tried to search the site if a similar query had been posted i.e. with this close a fit (1 cm) difference. I did not find any. Hence my post.

Thanks to let me know.
The sizing chats provided by manufacturers are only really a guide. One should never pick a size based on them alone. 

The only way to select a correctly sized frame is to test ride bikes of different frame sizes. As mentioned in comments, body proportions make a big difference.

Don't approach a possibly too-large discounted bike with the mindset of 'can I make this work?' Get the bike that is right in the first place. There will be other deals that come along. Also, remember that with a used bike you'll be doing maintenance and replacing wear items such as the chain and cassette sooner than with a new one.