I notice some of you have posted similar topic previously. However I like to address some of my concern regrading this topic because Oda (in manga) always give his readers (and One Piece Lovers) some vague ideas regrading the possible romance relationship in the story. Although I admit One Piece emphasize with Friendship, Adventure, Team-Work, Dreams and many more… but you cannot declined the fact each character build "love" relationship upon each other.
Firstly, let's discuss the possible outcome for Luffy:
Luffy & Alivdia - This is a very funny combo if they ever build a relationship. Back at Loguetown, Alivdia Quote [Episode 52] "I cannot forget you are first who punched me… when you hit me... I feel... and I like powerful man, I want you to be my man, Luffy." We know how Luffy response [Episode 52] "No Way, I Decline." We also awear Alivdia stop loving Luffy when Luffy was trapped by Boggy [Episode 52]. Therefore this pair cannot be together because Luffy don't love Alivida at the first place. This two can only be rivals. But certainly some people may say love relationship starts with rivals.
Luffy & Robin - This is an interesting debate. How can a 28 years old pretty and mature 'sweetcake' loves a 18 years old kid (Luffy mostly act on his will, not with his brain)? Then how come I stress the possibility between Luffy & Robin? After Luffy Crew escape from Alabrasta [Episode 130] Robin was on their ship "Monkey D. Luffy, you will not forget whatever you did to me…" then Sanji (heart broken) shouts "Luffy, what you did to this beautiful lady?" According from readers point of view, that scene can only mean one thing: some 'naughty' issues involved. Thank god Oda explained the situation using flashbacks. Although Robin is still very mysteries, she spoke truly to the Luffy Crew [episode 130] "you let me live while I want to die, that is your sin. I have no where to go nor any home to stay, let me stay on this ship…"
From my point of view, the above image can deduce as a girl was just break up with her boyfriend (her hope, her dreams, her faith are gone...) and want suicide. At this moment, her savior, Luffy, come to the rescue for her. Robin may not have feelings at the begining. With time, she grow attachment with the crew and build a bond between them. Robin finally find friends who can accept her of who she is and she admit so in [anime, chapter 359]. Therefore, Luffy gives Robin the strength to move on and forget her past.
Conclusion: can Robin bulid a love relationship with Luffy? my answer is No. Because Robin more likely loves Zoro (debate in Zoro's part). However, Robin loves Luffy as her companion, as her friend, as her 'family'.
Luffy & Nami - Observationally, Nami depends on Luffy on various occasions. The battle with Arlong finally solved Nami's pain and Luffy accepts her as his companion. No matter how much Nami loves money, no matter how much stupid things Luffy did to the ship and to the crew, Nami will forgive Luffy because he saved her from the evil within her heart. Although Nami didn't show her love to Luffy in the manga, but Nami does care for Luffy [Episode 8] when Boggy destory Luffy's hat, Nami is willing to help Luffy to fix the hat. Recall, during the time Nami hate pirates. Also in [movie 4 - dead end race] Luffy ask Nami to fix his hat again. Honestly speaking, the actions of Nami on Luffy really seems like Luffy's Wife (hahahahaha)
Let's us look at Zoro's Outcome:
Zoro & Tagashi - this duel may have a chance to be a couple IF!!!
- Zoro is not a pirate because Tagashi is a Marine
- Zoro didn't lie to Tagashi in the first place
- Zoro don't run away from her (Zoro's ONLY ONE who he ever feared)
- Tagashi don't charallage Zoro for a match
- Zoro willing to forget Kuina's Death
Warp UP: Zoro & Tagashi can only be enemies, and Zoro is too dumb to feel love relationship anyways
Zoro & Nami - Since Nami's heart have Luffy, I don't see how can Nami loves Zoro. They are companion and friends, but cannot be lovers.
Zoro & Robin - please let me explain why Zoro and Robin is a possible match.
Out of the entire Luffy's Crew, Zoro is the only one who is cool enough to maintain his swordman's role. As the story goes on, Zoro respects Robin while Robin also respects Zoro as the way it is. Let me recall [episode 135] does Robin offer her Jacket to Zoro, afraid he may catch a cold? Come on, think about it! Only Sanji will offer his jacket to any girls he saw because he loves girls from his first sight!!! I never heard a lady offering her jacket to a men (espeically zoro). Why would they pair up catching south bird in Jaya? When they face 'God' Emeru in Skypiea [episode 180], when Robin got hit by the Lighting from Emeru, did Zoro instantly come to protect her and quote to Emeru "but she is a women…" Look in the eyes of Zoro in that episode!!! it is like I will kill you because you hurt my woman! (hahahaha) It seems Oda pair Zoro and Robin together often because Zoro is the only one in the Crew mature enough to communicate with Robin (interenally speaking). Even in water 7, when Robin said she is leaving the Crew, Zoro is the only one who are rationalizing the posibility Robin may not act on her own? [anime, chapter 340-341]
Conclusion: Seems Robin don't mind starting a relationship with Zoro.
Let's look at Sanji's Fate:
Sanji & Nami - One Piece Fans will say Sanji loves Nami the most. But since Nami loves Luffy in her heart, Nami only flurtes in front of Sanji so Sanji will serve her as a Queen. Funny to say, when Sanji wants to touch Nami, Nami always gives Sanji the One-Two ^_^ [episode too many, cannot references them]
Sanji & Robin - same idea, since Robin's mind with Zoro, Sanji can only serve Robin with alot of good coffee!
Sanji & Posche (Foxy's Babe) - possible match, however same idea as Nami's
Conclusion of Sanji - Mr. Prince (but unlike James Bond of 007) and girl slave forever with no luck of having a girl (poor Sanji)
Let's look at those that we are most certain they will be together eventually:
Usopp & Kaya - [episode 17] Usopp ask Kaya don't stop him… but interenally Kaya don't want Usopp to leave Syrup Village
Smoker & Hina - [episode 127 & 130] Hina complains everything Smoker is doing with her and the strawhats. Sometimes I wonder does Smoker noticed Hina loves him?
Viva & Korza - personally, I don't see they can become a couple according to manga.
Jonathan (G8 Commander) and Jessica (Main Chef in G8) -
Lastly What About Chopper?
Please remember Chopper is a reindeer. No matter how much I like Chopper, at this moment, Oda didn't plan any love relationship for our poor Chopper because he IS a reindeer.