Lisnaholic

Good and bad news from me, I'm afraid, Ilpoxi !

Firstly, the good news: as a Brit, I would certainly pronounce "thriller" as "thrilla". It wouldn't, however be a very accurate rhyme with "bar", which I presume sounds very similar to "car" and "are", with a longer, more rounded vowel sound. Actually, imo, a rhyme which is not a precise match is often more effective than a predictable, perfect match. I'd say that matching moon and June, tears and fears is not going to make for good lyrics.

I'm no lyric writer, but reading your lyric, I wonder about the natural stress of the words. I hope this conveys how your couplet would naturally sound in spoken British English:-

FILL inda BAAR
LYK a THRILLa

( The last syllable of thriller is short and very unstressed, exactly like the single word "a" in the middle of the same line. )

Good luck !

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"Am I enjoying this moment? I know of it and perhaps that is enough." - Sybille Bedford, 1953

Ilpoxi

Thank you for a good analysis and actual aspects, I appreciate that. But I'll be satisfied with the rhyming of just long A vowels.

By the way, maybe it's about how you decide to say it in a song (if you don't think about the stress factors in the spoken language):

FILLIN DABAAR
LYK-A THRILLAA

(?)

Blarobbarg

If I'm pronouncing this right in my head, those two things DO sound like they should go together as a slant rhyme. Unorthodox, but I like it.