The way to make sure your students all pass is to do your job, those students need a teacher that cares and not one that 'needs a job', and preferably one that does not start off with the self-reinforcing viewpoint that a good fraction of them are too dumb to learn the material on offer.
Seriously, consider changing jobs to something with less of a negative effect on people's lives.
I've been on the receiving end of this attitude and it harmed me quite a bit, later on, with better teachers some of the damage got fixed but I most certainly would have traded two of my math teachers that 'needed a job' for some of the (much) better ones. Thanks to Fred Pach and one Mr. Groot I'm not a total loss at math and it ended up not being my skills but those of the teachers that were deficient.