That statement, made to Horthy in April 1943, did not reflect the stage reached by that date. It reflects an earlier stage, with the Jews unfit for use as forced labour imprisoned in the Polish ghettos and slowly wasting away from malnutrition. There is no hint of an active killing of the non-working Jews, a stage that had almost reached completion as of April 1943 in the General-Government.Which of course wasn't the only one statement in which Hitler was not only showing his knowledge but also setting or confirming the policy. E.g.:
"If the Jews there don't want to work they will be shot...If they cannot work, they must rot. They should be treated like tubercular bacillus which could attack healthy bodies. That is not cruel—if one keeps in mind that even innocent natural beings like hares and deer must be killed so that no damage occurs."
Also, there is a third group of Jews that Hitler did not mention, namely those fit for labour who were not resisting and were being employed in war production. Why he did not mention that group, which was important to the German war effort, is unclear; it may be that his sole purpose was to impress on Horthy what should be done with Jews who were not prisoners working for Germany as forced labourers, as was still the case with the Jews of Hungary, rather than to describe the total situation.
If Hitler was not concealing his knowledge of what was happening in Poland in April 1943, the description he gives of the conditions for Jews in that country suggests that he was not being kept up to date with the situation on the ground.
Which one is that? There is no statement by Hitler in which he uses words to the effect that he had specifically ordered the killing of all Jews under German control. There are only statements in which he says that the war which the Jews had allegedly caused was going to result in their destruction.Including the one that can be best characterized as Hitler's decision to kill the European Jews (I think this is the one existing that you meant).