For "educational purpose"
1)you can simply use multiple Google accounts on target phone,just add your google id in Settings>Add account,synchronise your acc with that of traget(which is already given) and you will have access to all the data through your account.
2)You might also consider to use spy apps.. many are out there,and those are simple to use.
But most importantly why do you think you need to hack her phone?
you dont trust her or you dont trust yourself enough to make a right decision while choosing your partner,and after hacking what if you really find somethin,would it make you feel better?or you would end the relationship,and what if you don't find anything at all?will you start trusting her,wonder where you will end up eventually
Whatever the reason you have got to hack her phone might be valid but there is no need to do it. Instead of hacking,or finding evidences for divorce consider to have a careful confrontation,if that doesn't work and you're not satisfied, just break up with her and get a better one,