Final sttlement for divirce

I got married on Feb 2010 & my wife is separated from june 2010 to till date.She took her all belongings including her jewelry with her and filed maintenance case & 498A in her home town.Me and all my family members got bail immediately from the district court. Now after too hard work of around six years i am able to make opposite party ready for mutual concent divorce(MCD). But the problem is she wanted the total money at a time & outside the court record. She wanted that i should pay the lump sump decided money in cash & at a time without any record.After paying the amount she will withdraw case 498A as well as she will give mutual consent divorce.I proposed for paying the whole money in two halves.Half at the time of Filing of MCD and another half on the final day of settlement.But she is not agree. After too hard effort also the opposite party is not ready for taking the money via court (Nazarat).She is telling to pay outside the court and that to be recorded in plane paper with her signature. Now my question is how much it is advisable to pay the total money out of court record.Whether her intention is right or not.How can i believe that after taking money, she will withdraw all the false cases against me.whether that plane paper will be sufficient to make proof that she has taken money from me in lieu of giving divorce.I request for all your suggestions