Does anyone out there have a translation for this saying?

Looks like something an OCR machine would generate for an Early Modern Gaelic text.

Can you point us to the source, please?

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Múinteoir Gaeilge - Irish Teacher
My "specialty" is Connemara Irish, particularly Cois Fhairrge dialect, but I can also speak Ulster and Munster Irish with native-level pronunciation.
Is fearr Gaeilge ḃriste ná Béarla cliste, cinnte, aċ i ḃfad níos fearr aríst í Gaeilge ḃinn ḃeo na nGaeltaċtaí.
Gaeilge Chonnacht (GC), go háraid Gaeilge Chois Fhairrge (GCF), Gaeilic Uladh (GU), Gaelainn na Mumhan (GM), agus Gaeilge an Chaighdeáin Oifigiúil (CO).

Yeah these are Scottish Gaelic words (with spelling mistakes) but I can't understad the sentence.

it means
"so to say is the demons to believe soul and shivering"..., or something like that but it doesn't look like a correct sentence, as it is now.

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Is fearr Gaeilg na Gaeltaċta ná Gaeilg ar biṫ eile
Agus is í Gaeilg Ġaoṫ Doḃair is binne

Many thanks for your efforts. The line was sent to me at the bottom of an email. I initally thought it might be a Scottish military saying. Again, thank you for your help.

It is Scottish Gaelic, and has some spelling mistakes. I'm not entirely sure about the last word, since the form seems odd, but I've adjusted it to something which does at least make sense:

Tha eadhon na deamhain a' creidsinn annam agus a' crith *
Even the demons believe in me and [are] trembling

* critheanachadh may be an older form of the verbal noun, but it's not in even my older dictionaries (spelling variations are very common, though, especially in older writings)

Sounds like something attributed to Jesus, but I don't recognize it from the Bible.
Editing to say that I found its probable origin in James 2:19 (in an old Bible):

Tha thu a' creidsinn gu bheil aon Dia ann
You believe that there is [only] one God
is maith a ni thu
that is a good thing, you [sort of like the Ozzie expression "Good on you"]
Tha na deamhain a' creidsinn mar an ceudna
The Devils believe in the same way
agus tha iad a' criothnuchadh
and they are trembling

criothnuchadh is also not in even my older dictionaries, but this is from an 1813 Bible and, as I said above, spelling variations were very common in the past (and many still survive).

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I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.

should be "annam", not "anam", which means "soul", as in Irish.

I didn't know "eadhon" could mean "even", I've learnt that with this thread

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Is fearr Gaeilg na Gaeltaċta ná Gaeilg ar biṫ eile
Agus is í Gaeilg Ġaoṫ Doḃair is binne

Yep, I missed that spelling error. I've corrected it above.

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I'm not a native (or entirely fluent) speaker, so be sure to wait for confirmations/corrections, especially for tattoos.

Many thanks to all of you scholars for decoding the saying! Well done!