Grammar GeekI think it is used to differentiate from a stranger.
Barbara, I know you are correct. It's just that I'm little confused about the structure of your sentence. It seems to me as if you have missed the noun phrase
a lover after
differentiate. If you had used the phrase, the sentence would read:
I think it is used to differentiate a love from a stranger.
I'm curious about the reason for missing that phrase. Perhaps, it's just the way the English language works