Cabachons Wont Stay on For Good!

I’m new to making resin jewelery and when it comes out right I absolutely love it. Some people have suggested I sell it. I’d like to but I have a fear in the way.
I make resin pieces that I then glue on cabachons(glass or plastic) to the piece. A couple of times, as I suspected one hard hit to the cabachon & it pops right off. I know about sanding a little both sides of the resin piece & cabachon, and that i’ll have more luck “fusing” the resin piece with a plastic cabachon but not with glass or precipus stones. I dont want to coat the the whole thing with resin again to seal the cabachon in because I did that & it turned out gloopy & horrible looking. What can I do to ENSURe the cabs dont ever come off? I cant sell something that is liable to fall apart. Please help! Otherwise my pieces just look good in photos & thats it.

Thanks! CC