When I taught in one of my classes at Xinzhu GV last Saturday evening, a student was asking me a question-- how to say "出爾反爾" in English. I got no idea about this one, so I asked Bruce for help immediately.
Emma, I think this may be the best answer I can get you.
I can't put up with him anymore, because he always breaks his promises with others. How can he change position this quick?
put up with someone 忍受
break one's promise 不守信用
change position 出爾反爾