Do they actually say your not good enough or is that something you made up.
Most people you see at the gym that have training partners are friends outside the gym first.
It could also be you are too hardcore
What are your stats? Do you lift insnane weights? How long have you been training? Do you look ripped and rediculous? Maybe people are intimidated by your awsome pressance.
I guess what im saying is dont be so hard on yourself there are thousands of reasons people might not want to train with you.