1. If it is a "personal comedy of errors" case then it is not acepted "socially". You may know well the reasons behind "societal acceptence" to accept a 498a IPC wife back and one need not be rocket scientist to think aloud socially on it.
2. Once she has tasted the "thrills of calling husband and In Laws to PS/Courts" she is bound to "experiment" again with the same or next person and this time she is bound to succeed 100%. Again depends on the environment she is keeping after HIS / In laws acquitall.
3. The second time it is going to be valid cruelties for sure.
4. Writing any undertaking does not solve any evidentary purpose in matrimonial cruelties situations per se as she can always back track from her statement and now say, husband and In laws put a kitchen knife over me and made be under pressure write such and such undertaking so now what is left for prooving "burden of proof" and BTW a 498a IPC is filed on "mere statement of wife is it not the social norm - prove me wrong on this prime facie statement that I just made" !
5. But at the time of withdrawing her Complaint before PS / CAW Cell if she makes such written statements then second time the effects becomes slightly less but the damage will be done effectively second time too as per connivence of certain sections of society's ward and watch persons personal interests are involved now.
6. I will say 50 : 50 chances in life if you are good at taking hurts in matrimonial life then your query is solved.
Like Sh. Reddy garu said most of 498a cases are connived by miss - guidence and to play revenge / havoc on In Laws families n to teach a lesson and the real true cases (genuine ones) are lesser statistically (conviction rate wise) and I call it a hype / propoganda created by media and like minded persons that 498a IPC filed by such and such lady is the "only" true case, had it been the only true case then national conviction rate would have said so !