If I have to file suit, will I win if the judge decides that the insurance company was wrong in rejecting my claim?

Not necessarily. Most disability insurance policies have language in them that will require the judge in your case to decide not whether the insurance company was wrong but whether the insurance company was "arbitrary and capricious" in rejecting your claim for disability insurance benefits. This gives the insurance company some leeway. It also shows why it is so important that you have an experienced disability insurance benefits or ERISA lawyer helping you with your claim as early as possible in the process.