To curry favor in the hope of being accepted by a group that has good or bad aims, you might want to first establish your bona fides/bonafides.
bona fides (plural noun) — also bonafides
bona fides
- good faith; honesty, sincerity, reliability, etc.
- proof or proofs of honesty, genuineness, etc.
Webster’s New World College Dictionary
bona fides
1: good faith : sincerity
2: the fact of being genuine —often plural
in construction
3: evidence of one's good faith or genuineness —often
plural in construction
4: evidence of one's qualifications or
achievements —often plural in construction
M-W
bona fides (n.)
A person's honesty and sincerity of intention: he went to great
lengths to establish his liberal bona fides.
[Treated as pl.] informal documentary evidence showing a person's
legitimacy; credentials: are you satisfied with my bona fides?
[Origin: late 18th cent.] Latin, literally 'good faith.'
The New Oxford American Dictionary
bona fide: 'in good faith'. It is used to modify some other word—bonafide intention. The expression bonafides (singular) is
used as the subject or object of a verb (meaning evidence that
somebody is who they say they are) as in: Her bonafides is above
reproach.
Subhash Jain; Improve Your Word Power (2021)
To help establish his bona fides as a leader of the underworld he
provided a fifteen-foot-high floral tribute at the funeral of a slain
gangster, and to protect himself he bought an automobile with armor
plating and bulletproof glass.
Marc Mappen; Prohibition
Gansters (2013)
Her orders were to devote a couple of months to journalism to
establish her bona fides before starting on her real task, which was to organize Spanish safe houses and escape route for French
Resistance refugees.
Sonia Purnell; A Woman of No Importance
(2020)
He shoots a policeman to establish his bona fides with the
gangsters, and later cold-bloodedly sends the chief of police to his
death.
Brian Docherty; American Crime Fiction (1988)
Many gang and low-level cartel members met in prison, where trust was
built over time and where their "credentials" and bona fides were
established.
Paul Rexton Kan; Cartels at War (2012)
We brought in an undercover agent named Tony out of Chicago who the
New York gangs didn't know, a wiseguy lookalike right out of central
casting. We made sure he made the rounds to all the bars and clubs
frequented by made guys, always in the company of our boy Hackey to
establish his bona fides.
Dan Addario et al.; Chasing the Dragon (2019)
Suspecting his bonafides, they mentioned their suspicions to their
August Uncle, with the result that he was forbidden to approach the
Vatican.
Frederick Rolfe; Chronicles of the House of Borgia
(1901)
That seemed to establish his bonafides. She really seemed
impressed.
Lee Bornstein; Slats and the Chanteuse (2019)
Exposition: As he lists his bonafides, we learn where Roman went
to school, that he chose to fight for his principles over personal
enrichment and that he's still an activist lawyer who's only doing
criminal work to support his fight for progressive initiatives.
Josh
Miller; Stuck! (2019)
Forbes spoke in a very low, very professional voice. "Mr. Zhol, we
checked the man. His bonafides are real.
Don Pendleton; Oceans
of Fire (2014)
With his shooting bonafides established, Chapman turned things up
a notch.
Joe Cox and Ryan Clark; Fightin' Words (2018)