Warba teaches Luke about what priests with no Force abilities could accomplish on faith alone, highlighting what he can do with his abilities if he believes.
She teaches Luke the mantra of the Guardians of the Whills: “I am one with the Force.
Luke, not yet a Jedi at this point, believes he may be able to learn something from her.
Warba is something of a junker and although she is not a Jedi, she is Force sensitive and has knowledge of the Force and shows some ability to harness it.