Like tears in the rain
The Weeknd is talking about the redundancy of crying in the rain because her tears would just be masked by the falling rain.
Also. This line (and the name of the song) are inspired by the film, Blade Runner.
To add, I guess you could say it as, after receiving the publicity, money and fame, you can’t tell the difference between the two, like tears in the rain. In other words, he can’t tell which girls would actually love him unconditionally and which just actually love his publicity, money and fame. “It’s pointless, like tears in the rain.”
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