多分俺は、今でもアリスを愛してる。
多分、世界で一位タイなくらい愛してる。
He's saying that maybe he still loves Alice.
How much does he love her? Is it "maybe" or "probably"?
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Sign up to join this communityHow much does he love her?
You can't exactly judge that based on these two sentences, but your translation is missing something important about what is said. Setting aside probably/maybe and using a dictionary definition of 多分,
多分俺は、今でもアリスを愛してる。 多分、世界で一位タイなくらい愛してる。
I probably still love Alice. I probably love her as much as the joint winner(s).
「一位タイ」 is usually used when talking about sports, but here it's used figuratively to refer to the ones he loves the most in the world. The 「タイ」 comes from the English word "tie", in this sense:
noun
5 A result in a game or other competitive situation in which two or more competitors or teams have the same score or ranking; a draw.
‘there was a tie for first place’