Meaning and local context
In Texas, “fixin to” means About to or preparing to do something. A highly recognisable Texas and Southern expression.
Example in context
A local example is “We are fixin to leave.” In plain English, that means “We are about to leave.”
We are fixin to leave.
We are about to leave.
How to interpret it
The surrounding sentence is important when interpreting “fixin to”. Use the regional sense above when the situation matches the example instead of relying on the word or phrase in isolation.
Tone and caution
It expresses near-future intention, not repairing something. Because this is informal regional language, tone and situation should guide whether you use “fixin to” yourself or simply recognise it when someone else uses it.