No, Go Au Pair cannot guarantee a visa for any Au Pair. Go Au Pair provides the Form DS-2019 and coaching/training to you to best prepare you for your Embassy visit and interview.

Issuance of the J-1 visa, like all non-immigrant visas, is at the discretion of Consular Officers viewing visa applications at U.S. embassies and consulates. This means even if you are accepted to an exchange visitor program and have received your DS-2019, the Consular Officers decide if you receive the J-1 visa.
 
(from the U.S. Department of State website, visit http://exchanges.state.gov/ for most up to date information and to learn more)

The objectives of the Introductory Workshop are to reduce culture shock, teach first aid and CPR skills and experience New York City. Some topics covered during the three day workshop include:

• Review of driving in the U.S. such as signs, rules, policies
• Movies, TV and music ratings
• American holidays
• American food
• Cell Phone billing and international calls
• Personal space
• Punctuality
• Educational requirements review
• Insurance coverage review
• CPR and First Aid Classes

The Introductory Workshop is an optional training in addition to the required 32 hours of training which is received in your home country.

The Form DS-2019 or “Certificate of Eligibility for Exchange Visitor (J-1) Status” is the basic document used in the administration of the exchange visitor program. This form permits a prospective exchange visitor to seek an interview at a U.S. embassy or consulate in order to obtain a J-1 visa to enter the United States.

The Exchange Visitor (J-1) non-immigrant visa category is for individuals approved to participate in work and study based exchange visitor programs, which enable foreign nationals to visit the United States in order to experience life in the U.S.

This means that before you can apply at a U.S. embassy or consulate for a J-1 visa, you must first apply, meet the requirements and be accepted to an exchange visitor program through a designated sponsor organization. If you are accepted as a participant in an exchange program, the sponsor will provide you with information and documents necessary to apply for the J-1 visa to enter the U.S.

(from the U.S. Department of State website, visit http://exchanges.state.gov/ for most up to date information and to learn more)