Flyboy2,
good question. At Ameriflight, failed checkrides are few and far between. The company is generous with training, and the training captains reputation and professional standing depend on that the trainee is properly prepared for the checkride. The training captain actually recommends the trainee. They don't recommend them unless they think they are ready. You will be well trained, the checkride usually is somewhat routine, almost a non-event. The other factor is that you can re-test during a checkride. On my first checkride, I was nervous, and blew my first approach. So I was allowed to redo it, and did fine the second time and the rest of the ride. So unlike an FAA checkride where they can't retest, I passed the ride.
After a while as a line pilot, you do so many checkrides that it is no big deal. You always want to prepare and take it seriously, but you will be confident and not have a problem. All the check airmen I have flown with or heard about have been very fair. If they weren't, they wouldn't be tolerated and they would not be allowed to give checkrides.
But I don't want to mislead you, if you make major mistakes and the trend of the checkride is bad, that is an unsatisfactory checkride. Then they'll give you re-training and another chance. If that doesn't work out, well, you probably weren't ready for the job anyway. Again, fairly rare. If you don't think you are ready for the checkride when they schedule you, then just speak up.
The interviews right now are tough and they are very selective given the large number of applicants and few positions available. So if you get hired, you probably have good skill and knowledge and operate cool under pressure, so you shouldn't have a worry.