Your question is a bit confusing as posted. "A judge" suggested you apply for house arrest, but you're concerned that a judge at your hearing may deny house arrest. House arrest is a form of punishment handed out by a judge; only a sentencing judge can permit house arrest. The probation department is in charge of administering that program. I hope you have legal representation in this matter. If you are unable to afford counsel, then the public defender's office in your county would be the place to seek representation. Good luck.
It is unclear from your question whether you are seeking pre trial house arrest or whether you are seeking it as part of a sentence. Hopeful, you have an attorney to represent you. It is always up to the Judge to allow it. Good luck.
Not sure what exactly your situation is but if the judge told you before sentencing to get hooked up with house arrest, that is an indication he will allow you to serve your sentence at home unless you do something stupid between now and sentencing like get arrested.
A lot of this answer would depend on what county your case is happening in. Bucks County uses house arrest very frequently while Montgomery County is much more difficult to get it. I would welcome the chance to speak with you about the situation. Give me a call at (215) 639-4400.
The above is a general answer but should not be considered specific legal advice for your case. If you would like to discuss the particular problem you are facing, please contact Geoffrey Hood, Esquire at (215) 639-4400