Meh, that's so bad. Consider the other guys in his crew. You have three perverts, a big ass liar, a shy kid, and lazy guy who just doesn't want to deal with things outside his own interest/goals (I fall in to this category ). We're only men. Unless you actually come out and say "whatever" you can't blame us for being clueless all the time. Especially someone as simple as Luffy.
Well...Nami had a lot of time to make her move on Luffy...she apparently thought she would have all the time in the world. Truth to be told, she should've known that, regardless of his faults, someone like him would eventually gain more than one female fan across the seas...and it was only a matter of time before one of said fans declared her love for him openly...thus, earning her a rival...
Honestly though...never before have I suffered so much to decide on a pairing. I just like Luffy with both of them equally, I can't chose. Couldn't he just have them both?
people should not take boa being in love with luffy or any body being in love in one piece seriously. oda only made boa fall for luffy for comedy. he does that. perfect example: sanji. no matter how hard he tries he ain't getting nothing from nami or robin