what would happen to non-jews but who looked jewish during WW2 in Germany?

For example, many people has some stereotypical "Jewish" characteristic such as having a large nose, brown eyes and hair and Sharpe faces etc, even though they aren't part of the Jewish faith or ethnic group. I know many Italians, Spanish and other south Europeans who can pass as being a Jew. The question is, what would happen to lets say, an Italian who lived in Germany that can be easily mistaken for being a Jew, will he be arrested? If so, how about a real Jew who changed his religion and surname in order to pretend to be Italian? Is there a chance for him to get away and survive the Holocaust?

Hitler probably killed them

Didn't matter what you looked like. What matters is your family tree. If you can prove that from your grand parents to you, ye were not Jews then you were fine. Only those who were Jews, had Jewish parents or more than two Jewish grandparents were earmarked for slaughter.

Appearance didn't matter; (circumcision was the biggest giveaway here) you had to fit the Nazi definition of a Jew, which was one or more Jewish grandparents. If someone changed their surname and pretended to be Italian, they were usually found out. However, many nuns hid Jewish girls in their convents, trying to pass them off as Italian.

Your right, German police etc, WERE actually trained to look out for stereotypical Jewish facial features, anyone who looked Jewish (according to the often bizarre stereotypes presented by the Nazi's - such as the classic Nazi description 'the swarthy dirty hook nosed Jew') would certainly come under a lot of scrutiny by the authorities
All Germans had to prove their ancestry, to do this they had to have proof of who their parents were, (i.e marriage certificates, birth certificates etc) they also had to have the same info on their grandparents (both couples) and in some Germany states even had to have those details of back to their great grandparents (all 4 couples) (there was a lack of constancy between all the German states, as the length of history was entirely set by the local senior Nazi Official, hence some were fine with grandparents, some wanted even more history
These certificates would all list a persons religions their parents religion, etc, some people got in trouble if (for example) their grandmother had a Jewish sounding maiden name,

people did pay forgers to change or create new 'Jew free' documents, how effective this was depends entirely on how good the forgeries are, (there are rum ours that several high ranking Nazi's had some Jewish genes in them, but had used their power to get records changed) ultimately I suppose someone who really 'looks Jewish' would probably have his documents examined more closely, than a Jew who looked German

This was only in Germany - outside of Germany in other fascist states such as Italy, they didn't bother with this quite so much, (as they didn't have the Germans fascination with genetics) they simply got all practicing Jews to register, (and got lists from Jewish temples etc)

If push came to shove, boys or men had to drop their pants and show whether some skin was missing from the religious mutilation.