“Love Island” alum Sharon Gaffka is not buying what Cierra Ortega is selling in her apology video for using an Asian slur … Sharon says Cierra knew full well what the hateful word implied.

Sharon — who was on “Love Island” back in 2021 — joined us on “TMZ Live” Thursday and we asked for her reaction to Cierra’s apology video for some past use of a racial slur online.

The thing that bothered Sharon the most was Cierra saying she didn’t know the “word held as much pain, as much harm, and came with the history that it did” — Cierra’s from Arizona, and Sharon says anyone with access to the internet in America should know it’s a hateful slur.

Plus, Sharon says the simple fact Cierra used the slur in a reference to eye shape indicates she knew full well the meaning the word carries.

Sharon’s of Asian descent and she says hate toward Asians has picked up since the pandemic … and, for her, this is another example.

For her part, Cierra — who was booted from the reality show after the posts resurfaced — says she’s determined to be a better person moving forward.