回答
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I've never seen a couple as memorable as those two.
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That couple sticks in my head more than any other one.
心に残る = to stay/stick in your head, to be memorable, to stick with you
回答
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These two are the most memorable couple ever.
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There's no couple that will stick with you as much as these two.
「心に残った」という表現は英語では
"stick with (you)"
"stay with (you)"
"memorable"
などがあります。
1つ目の例文は意訳に近いんですけど、2つ目はかなり直訳っぽい表現だと思います。
通じるのですが、1つ目の方が最もナチュラルに聞こえると思います。