"Not even after twenty years could he forget about the woman?"
Translation:Ani po dvaceti letech na tu ženu nemohl zapomenout?
Something is not as smooth as it should be, I would expect some continuation on a relative clause: "... na tu ženu, kterou ...". Stressing "na tu ženu" just like you propose sounds a bit incomplete or just strange. But I can't find any strong enough objection so I will add it.