It’s not a contest and I ain’t on no conquest for no mate
I wasn’t looking when I stumbled on to you, musta been fate
Em was just playing things cool when he found love/drugs (is there really a difference?), so it/they took him by surprise
Em wasn’t looking for no one, he wasn’t trying to find love but he eventually met it anyways unexpectedly, he says it must have been fate, destiny put her in front of him without him wanting it. Eminem is saying that no other girl can compare to the girl that he had (despite the fact he wasn’t looking for any particular girl) and he won’t look for any other girl because no other girl is better than his last one.
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