During negotiation in any kind of international agreement, what will you do if the other party insist in using a governing law which you can't accept?

Well the Parties need to adopt the forum of convenience. That could be the place where the whole transaction or most of the transaction will be carried out. It could be place of business of the Parties. Or where arbitration should be held in the event of dispute.

Alternatively, the Parties may have to agree on a commonly accepted law to govern their business.

I will agree to use the most commun law such as the UK/English Law

I will consider the governing law and ensure that it conforms to an International standard. If not then I would refuse to abide by the govermental law because international law is the basic of justice and equality. 

Generally in international commercial law, many countries have similar commercial clauses, except if there is a special law which relates to the national security.   Conditionally you can accept a governemtn law, but the jurisdiction of law and Dispute resolution must be under the Board where from you are providing Products and / or services.   In this case adopt diplomatic words and also refer the counter clauses of your own country which defend you from fruture legal or commercial disputes as a legal safeguard.

Depends ! if you are procuring Services or Products in the country of which you intend to keep jurisdiction, you can ask because business is being conducted in that country, therefore any dispute should be subject to same country. As a second option you can say that in case of any disputes same shall be resolved by adopting arbitration rules of SIACsubject to the condition jurisdiction of courts will be of your choice. Lastly you cann sttle for a jurisdiction which may be conviniant to both the parties (if not native of either of the parties). 

Agree with answers of colleagues.

Good question.

You need to play it smart and try to manipulate.  To avoid getting into that point you have to show your opponent that you are stronger than him and then he will not put you in that situation.

Agree with Mr. Adeniyi Shoda, as most of the international Agreements are governed by "international Arbitration Terms", that stipulated in the agreement text itself and agreed upon by parties concerned in case of any deputes.

An international agreement will define the law to be used with respect to implementation of the agreement. This will define the jurisdiction and the legal processes to be used in the event there is a dispute. Unless you vary this condition you are bound by it. The other party is obliged to comply with the agreement, a deviation from this can only be implemented if the both parties agree to the change.