If sectarianism makes the world a dangerously divisive place, it seems logical that someone born of mixed cultures, religions and ethnicities would happily embrace an integrated identity.

In reality, a blended heritage can lead to personal conflict and confusion. Cherien Dabis — writer, director and star of the highly original comedy “May in the Summer” — explores what happens when a bright and successful author loses confidence in her seemingly secure self-image of above-the-fray inclusiveness.

As May, Dabis (“Amreeka”) is both persuasive and sympathetic when her sophisticated character — a New York-based writer engaged to Ziad (Alexander Siddig), a Muslim scholar from Columbia University — travels to her native Amman, Jordan, for a wedding that no longer seems a good idea.

There, in the country’s capital, May resumes a frosty relationship with her divorced, Arab, born-again-Christian mother (the great Hiam Abbass), who refuses to attend the wedding because of the groom’s faith. May also finds her unreliable white-American father (Bill Pullman) reaching out while she also navigates confusing family history with her restless sisters (Alia Shawkat, Nadine Malouf).

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Above all, marrying Ziad loses its false security for May as she becomes re­acquainted with her conflicted roots, all while warming up to a kind Palestinian tour guide (Elie Mitri).

Shot in Amman’s middle-class environs, the film (inexplicably rated R) is deceptively light in tone, given such strong themes as infidelity, abandonment and religious intolerance. Dabis covers a lot of ground as a storyteller while delivering a smart, focused performance.

Thom Keogh: tomwkeogh@gmail.com