I just killed a bottle of a sweet chili sauce that I’d been using for … a few years or so. My guess is that if it doesn’t smell/look “off,” you’re fine.
If not, then it’s probably safe to eat, even though you probably don’t want to, since the organisms that cause detectable spoilage generally aren’t harmful.
If it does look and smell fine, then it’s impossible to tell. The organisms that cause food poisoning can’t be detected by appearance or odor, and could have contaminated the jar any time it’s been open and will have multiplied whenever the jar was subsequently at close to room temperature. On the other hand, if it hasn’t both been open and subsequently at room temperature, then it’s very likely to be safe.
ETA: Even being open for a brief time can allow contamination, and being above refrigerator temp for even a fairly brief time (on the order of half an hour, I think) much later can be enough to make you sick. Obviously risk increases with prolonged exposure to air and warmth.
Probably fairly acidic as well. Cold temperatures, salt, sugar (in high enough concentrations), alcohol and acid all inhibit bacterial growth.
That’s why things like pickles and mustard hardly ever spoil in your refrigerator. They’re loaded with salt and vinegar, and kept somewhere near 37 degrees- very, very few bacteria will grow in those conditions.
I’d imagine the marinade is similar- maybe not as salty or acidic as mustard, but probably similar to salad dressings which also rarely spoil.