poor, sure, more: words often used for rhyming at the ends of poetic or lyric lines (random example: I'd like to ensure / That our love will bring more); non-rhotic speakers will claim that these words mutually rhyme as indicated in the phonetic renderings paw, shaw, maw.
With occasional exceptions, native-born Canadians using English are rhotic speakers, their Rs being fully sounded, even after vowels. However, large numbers of immigrants have been welcomed to our shores bringing non-rhotic dialects. Their speech pattern is rendered roughly by changing all the relevant Rs to Hs. Many will also use a pronunciation element known as the "intrusive R", as in the verse's third line (flawR). This speech variation, invoked in this particular instance, might lead many North Americans to feel that the word floor is under discussion.
In Canada and substantial portions of the northern US, as reported by our staff-member and poetry coach Larry, the Mary/marry/merry merger, relevant to a related group of words containing the letter R, simplifies the varied pronunciation of vowels prior to that important consonant, with major benefit in crafting rhyme-pairs.
You can find lots of other verses on this blog under the listing "Poets' Corner". Click HERE.