Hey I'm looking for a manga were the female lead is cool headed at least in terms of the guy she likes. For example she see's the guy she likes making out with another girl and just smiles, or walks off. She doesn't let things get to her. i've already read Aishite Kudasai, Sensei and stroke material Warau Kanoko-sama and it's sequel.

You're heading toward tsundere territory with this. There are a lot of tsundere comedy romance mangas out there. But you're not asking for that, so I'll try to keep the tsundere down to a dull roar.

Off the top of my head:

REC
Mysterious Girlfriend X
Suzuka
Maison Ikkoku
Love Hina this one is a classic abusive tsundere

Shoujo romance mangas pretty much always have the girl being earnest and pure hearted - this tends to result in her not being very cool headed Often there's a sidekick to a female lead who meets this specification - the denpa girl in Fruits Basket comes to mind.

That said, you can go the other way for fun results, too - the female lead is so into the male lead that it's downright weird:

Koharu no Hibi
Mirai Nikki (violent - definitely not a romance)

http://senile-seinen.blogspot.com/

Something like Kawaii Oresama surely works.
Aku no Hana
Koi wa Tenka no Mawarimono
Last Game
The Prince's Cactus
Cheese in the Trap
Tonari no Kaibutsu-kun
Kuroneko Guardian

Or check this out:
Female Dominance
Cold Female Lead
Emotionally Strong Female Lead
Independent Female Lead

Or MAYBE....

Male Lead Falling in Love First

And don't trust this tag unless combined with other one in the Advanced Search section:

Physically Strong Female

Maybe Hina from Hayate no Gotoku.
Also male lead's girlfriend from Sakuranbo Syndrome (warning: it's a bit on the mature side)

Beauty Pop

In the Chocolate

朝露の少女。

“The longer we live, the more weight we carry in our hearts.”

Quote from Winterashes1

For example she see's the guy she likes making out with another girl and just smiles, or walks off.

Quote from senile_seinen

Mirai Nikki (violent - definitely not a romance)

Uh... I usually don't mind wrong recs, but if Yuno sees Yuki kiss another girl, she'd kill both. She almost killed for Yuki smiling at another girl.
I think you misunderstood something because all your suggestions are wrong. He's not definitely asking for a tsundere or a yandere, more a kuudere maybe, but I think only some of them will fit.

Anyway my 2 cents on the matter:

Nozoki Ana (Emiru)
Highschool DxD (Rias)

What I like in Trivial Pursuit style. Pick your category:[img]http://i379.photobucket.com/albums/oo233/Reid4891/Manga/trivia-1.jpg[/img]

Quote from reid1

Nozoki Ana (Emiru)...

Emiru is not cool, she's cold, frozen cold. And she like to tease others too, so a bit warmy sometimes, like a fried ice cream. Yum! 😁

grammar mistake is intentional, grammar nazis need their entertainment.

Beauty is The Beast

Youko x Boku SS
Tonari no kaibutsu-kun

Beauty Pop, definitely.
Gokuraku Seishun Hockey Club, also a must.
Joousama No Inu - guy falls for her almost immediately, but she doesn't...until almost the end xD
Warau Kanoko-sama and Koi Dano Ai Dano
Stroke Material
Last Game
Tonari no Kaibutsu-kun
Nekota no Koto ga Ki ni Natte Shikatanai
Watashi ni xx Shinasai
Akuma to love song...kind of.
Hana ni Arashi (girl is not exactly cold, but hard to get and physically strong)
Saiunkoku Monogatari - girl is indifferent to guys
Watashitachi ni wa Kabe ga Aru - not really cold, as she's looking for a boyfriend, but she's cold in a way that she totally ignores the love advances of her popular childhood male friend
Kodomo no Omacha
Takane to Hana - girl is not cold but pure sass, female dominance
Oresama Teacher - girl is not cold, but physically strong and indifferent to girl-boy romantic relationships despite all the boys around her
Namaikizakari. - girl gets jealous, but definitely hard to get

Hope that helped!
😀

"FEED YOUR OWN EGO, I'M BUSY."