We have a website with 2 URLs the name of website is like betteroffers but because it is very long we bought 2 urls like betteroffers.com and betterO.com, which redirects to the first. (The addresses are just examples and our website URL has 16 letters!) So I want to know how a user feels when using a shortened link like betterO.com, which redirects to betterOffers.com and I want to know how a user experience when is going to a website with very long url (16 letters). At last do you suggest we use a complete, long url or a short and meaningless url? Why?
I was researching this exact subject just a couple of months ago. (Our domain is also 16 letters.) We decided to go with the long-form URL because we have a well-established brand using the full domain name. We'll use a shorter version only in contexts where people will likely be manually entering the URL on a phone (at in-person events like fundraisers, conferences, and awards ceremonies).
However, if your brand isn't well-established yet, it's probably worthwhile to use a shorter URL. Gaebler.com found a correlation between domain length and popularity of website. Shown here, the 1,000,000 most popular sites.
Note, this is correlation, not necessarily causation. It's possible that the larger more successful sites have a better marketing budget and thus are more able to afford shorter domain names.
You could also try looking at how much of your traffic is direct vs how much you would expect to be direct based on industry benchmarks for websites in your sector. If you get significantly less direct traffic than normal, one possible cause could be that your URL is too long to type easily.