All to prevent her secret from ever coming out.
This basically is the engine that drives the plot of the first and greatest noir cum private eye story ever : Raymond Chandler's FAREWELL MY LOVELY (1940).
The city of quartz passes for diamond
From 1920 till 1960 (the years of the very height of high modernity) Los Angeles's population repeatedly told the census people that it had the highest percentage of native born white protestants of any major American city - most residents also claiming to be born with clearly Anglo-Saxon names.
Some - a few - might have been telling the truth - but not many.
Adapting your real name to sound more native born Anglo Saxon did not just start and end with people in Show Biz or LA : it was a national passion under Modernity.
And claiming to attend a mainstream protestant denomination (once every decade - for someone else's funeral or wedding) never ever hurt any 'passer' either during the era of Modernity.
And so what if you were originally a swarthy Italian or a light Colored - who could tell anything anymore in a nation addicted to having deep tans and peroxided hair ?
One of the greatest successes of Modernity film's censor board (the Breen Office) was in preventing any hint on screen of deliberate miscegenation : the races deliberately choosing to sleep together.
But perhaps Modernity's greatest fear was of the screen showing examples of what later is revealed to be unintentional sexual miscegenation.
That Mary Douglas-like nightmare of the supposedly white native born protestant WASP bonkette in your Big House bed actually turning out to be a swarthy dark , foreign and Catholic crop picker from out in the dirty fields .
In the early 1940s, the Allied nations justified the conscripting of their young to possibly die as necessary to protect the vital "small c" catholic concept that 'all men are brothers'.
Meanwhile, Joseph Breen's office, working (ultimately) under the direction of the Pope, struggled hard every day to deny this fact ever appearing on the screen.
But then the race-traitor Raymond Chandler (that rare southern Californian who truly was white protestant anglo saxon and native-born) slipped a catholic darkie 'past' Breen : and Noir was born ...