Are there any love interests in one piece?

Answer 1

No, there aren't. While there are some people that seem like they'd obviously become a couple (i.e. Usopp x Kaya) and others that have crushes (i.e. Boa Hancock), Oda keeps the romance out of One Piece.

Answer 2

There's a bit of ship tease between Allen and Lenalee if you choose to see it that way, but nothing concrete. Rhode is very upfront about her affection for Allen. Then there's Krory and Eliade, which was canon. Outside of that, no, there's no romance in the manga or anime.

Answer 3

Well, in the anime there is one scene, where Road kisses Allen. There is the same scene in the manga, but nothing else.