im looking for manga where the boy falls in love first and has to work hard to make her fall in love with him. the boy has to be strong and cool, not a baby face boy or dumb. and it also would be nice if the boy is mean and very stong, but very sweet when he is with her.
so a manga with lots and lots of ramance and cliche is ok!
i dont like dumb, simple minded characters! but if characters are simple minded but the manga is still very good, just tell me

Love hina?

kinda fits it, but the lead doesn't develop into someone strong until a bit in.

Lilim Kiss
or
Tona-Gura!

It's been a while since I've read Lilim Kiss, but off the top of my head this is one that seems to meet the majority of your criteria.

Tona-Gura!, although not fully scanlated yet, also looks to be a good choice.

Hmm.... Im not really sure if this one fits all your criteria but Cutie Boy is pretty good

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"I have the true feeling of myself only when I am unbearably unhappy."

Hm. You're So Cool kind of fits into that. Also, Chocolat could qualify, although it's a reverse harem, I think.
Sugar Addiction, if you're okay with triangles and the constant question 'who'll she choose?'.
Akuma de Sourou kind of?
Suki ni Natte mo Ii No? maybe not exactly mean, but the guy was definitely scary at the beginning

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Current avatar features Badou from Dogs.

I'm no Angel!!
Gakuen Alice
Fruits Basket
Special A

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Goong?
Hot Gimmick? ( hmm ... undecided on this one)

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I agree with the people who recommended Special A, I'm no angel!!, and Akuma de Sourou.

but definitely not Hot Gimmick. That is one of the worse I've read.

I'd also recommend:
Kaichou wa Maid-sama! (the guy isn't really mean, but he's definitely a stalker. xD and he can be kind of annoying to the girl)
Venus Capriccio (the guy is nice as hell, but he falls in love with the girl first. it's very cute)
kiss/hug (the guy isn't mean, just very.. presumptuous? there's only a chapter out so far though)

I would say Hana Yori Dango

The guy falls in love first while the girl hates him at the beginning. He's very confident and arrogant but with time her attitude towards him changes...
I know it's very long but it's worth to read it for sure. It's a classic

[m]I''s[/m] is a must read. Clannad and Kanon are pretty good.

And people are going to laugh, but Tenjho Tenge Actually fits your description quite well.

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Listen here
Livin just to keep from dyin

I read the thread backwards, but although Akuma de Sourou fits the "cool guy" description, the girl doesn't know that the guy likes her really. I guess she isn't totally confused for 11 volumes but doesn't know just exactly how much he really cares for her. *shrugs*

I'd recommend DNAngel but since the character is too young at 13 years old (all these other bishies in the other recommended titles tend to be between 15-18 years in looks, but maybe the mangaka just made them tall...) and probably a bit awkward, it wouldn't be a priority according to the OP's requirements.

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My avatar was Yves Saint Laurent's The Black Evening Dress (with big bow) first shown in 1983, photographed from his 2002 retrospective and final show. [color=#CC0066]Check out some of his collections for free (pre-2008) HERE[/color] courtesy of FirstView.

School Rumble
Love Collage
Mr. Full Swing
Tuxedo Gin


SeeYa

Gorath

http://www.mangaupdates.com/series.html?id=6530 otomen kinda fits your description but with a twist
http://www.mangaupdates.com/series.html?id=5722 black bird has a tiny bit of smut though
http://www.mangaupdates.com/series.html?id=5451 not exactly nice around her in the beginning but highly recommended
http://www.mangaupdates.com/series.html?id=596 fits everything except for being the cool guy. its very cute though
http://www.mangaupdates.com/series.html?id=368 love monster is good but really cliche
http://www.mangaupdates.com/series.html?id=1512 people already recommended this but i'll 3rd it =]



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