...but romance isn't the (only) main focus of the manga. Also, the one with the unrequited love should be male. It's okay if it's not really an unrequited love, but the girl's feelings aren't made clear to the readers in the beginning. No huge age gap. That's it, thanks!!

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

Frogman
Smash!
Ginen Shounen

I's
yume de aetara
suzuka
hetakoi(ecchi)
open sesame
kimi wa pet
kimi wa midara na boku no joou (ecchi)
More in my lists, have fun reading

I like turtles

Thanks, but most of these manga are only about romance. I'd like it as a subplot

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

High-School DxD (Novel) ?
The main female character started to love the protagonist after the second volume of the novel.

Tonari no Kaibutsu-kun?
It's pretty much fun 🙂

Suzuka - romance not only focus but sports as well, but still the romance is quite heavy
Little Jumper
Hanza Sky - dropped by Scanlation group
Maji de watashi...
Ookami-san to Shichinin no Chuugentachi - well from the description you cant really tell the plot 😉

Thank you for your answers 🙂 Suzuka is only about romance, though; yes, there kinda is this sport theme, but it's reeeeally slight.
Any other suggestions?

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

History's Strongest Disciple Kenichi... maybe ?

Though I don't like Kenichi, you quite understood my request; I guess it's a good example of what I'm searching for, not great but good, thanks 🙂
Not being harem is a plus

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

You gotta try "Yankee-kun to megane-chan"...

Baby Steps is quite good. Bonnouji seems heavy on romance because its a slower paced slice of life but is fantastic and a gem of a series.

I don't know about Yankee-kun to megane-chan because I heard that it was pretty inconclusive at the end.
Baby Steps and Bonnouji are both good, I have them on my reading list though 🙂

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion

It's a pretty difficult request TC. In a non-romance manga with a male protagonist, the romance usually comes into play when a girl comes along who is admiring of what the male hero is doing (the main focus of the manga)... it just doesn't really work to have it otherwise. You can't have a male hero who's focused on fighting or w/e to be pining like a little b**** over some girl. That's reserved for utter disgusting trash like Suzuka.

Having said that. I think Green Boy kind of works. The guy likes the girl and sort of starts fighting because of her... and her feelings aren't obvious (or even present?) at first.

I know it's difficult, that's why I asked here XD
Then again, being in love doesn't have to mean whining all the time. And what's more, I never said that the guy must be the main character. Maybe now the possibilities are wider?
Thank you for your suggestion, but Green Boy is in my reading list too.
Sorry for my poor English.

My current top 3:
Fullmetal Alchemist
Pandora Hearts
3-gatsu no Lion