A homeowner can't be forced to sell, except by operation of law, such as a court order or foreclosure, etc. Even though you can't be forced to sell, you may still be liable for damages, specific performance, or broker commissions. We don't know what's in your specific agreements with your broker and your buyer, and even if we did, we would recommend that you seek legal advice from an attorney.
I am a real estate broker qualified to advise you on California real estate matters, not the law. If you desire legal advice, consult with an attorney.
Best of luck!