It's been demonstrated many times that when an average person aspires to have a Latin tattoo, an engraved ring or simply a clever motto they likely to have the desired Latin phrase badly mangled, often to the point of complete nonsense. I do my best to verify the spelling of all the phrases that appear on my site, but I would recommend that people check twice every tiny bit of Latin that they want to use for any purposes, no matter where it comes from. The good news is that this is not so difficult!
First of all, unless you are relying on someone who is trained in Latin translation, never use a phrase that, in your personal opinion, aptly renders a phrase in your own language (English, French, German etc.). Without proper knowledge of Latin it is often impossible to translate even a single word by simply looking it up in a dictionary, never mind an actual phrase. So, if you have something unique in mind, go to a translator. You will be glad you did. However, there is a universe of Latin phrases out there. You are free to pick out of many well-known quotes and mottos. The trick here is to be aware of misspellings and OCR errors. You really want to verify your selected quote by using at least two printed sources. I do not suggest that you buy a book of Latin adages and try to find your favorite Latin phrase there (although your money could not be better spent if you, in fact, do so). Google Books has numerous scanned published resources. Many of them come from the glorious times when not only the writers and editors knew Latin, but even typesetters and book-binding workers! All you need to do is carefully copy your Latin phrase into the buffer and then paste it within quotation marks (otherwise the search will be too broad) into Google Books search field. Then open the actual scanned pages and verify that the phrase you are intending to use is indeed spelled the way you thought it was spelled. Oftentimes, you will get a nice translation as a bonus!
If the phrase you are tracking is fairly common, you can probably go to a collection of Latin quotes. Here is one such collection on Google Books:
Now, what if you are not finding the Latin phrases you were hoping to verify? It is quite possible that they have been misspelled. If so, identify a few words within a phrase and run a search on those words only (remember to use quotation marks). This will very likely bring up the Latin phrase in its correct form.