I like Yaoi and I've read almost every yaoi you can name, so now I'm sort of reading Josei smut manga but all the sex scene are soo mild, unlike any yaoi manga i've read (you know what I mean). I'm used to yaoi which makes my blood rush every time I'm reading it, but every time I read some josei manga, I always ended up with spineless woman who are so stupid that I gave up reading it. And so few of them are with a decent story and romance.

The only place where I can find a hetero manga with adult women and hot sex scene is a Hentai. -_-
how come Most of yaoi manga with explicit scene didn't fall to Hentai category, but a hetero manga with a bit explicit sex scene falls directly to hentai category?

Bottom line, is there any Josei manga with hot sex scene and interesting story and romance, just like any Yaoi manga that I can find?

I know what you mean, believe me...
However, there are a few things to take in account regarding what those categories actually represent.

First and foremost: yaoi is porn. Most yaoi publishers specialize in erotic content and meddle with hentai as well. That's how the manga sex industry is, men get Hentai, women get Yaoi (porn with a hint of romance). So, you can't really look for an equivalent for yaoi outside of porn. When you take a step back to look at it, Yaoi is very over the top in terms of representation of sexual activities, the most skilful artists do take reference in gay porn. The sex isn't less hardcore than in Hentai (both make use of all possible fetishes and pervy tropes, including the most transgressive ones), technically Hentai should be a good fix if you want that kind of hetero smut.
I do know that BL aren't all super porny and the genre is very diverse but Japan doesn't have the most forward culture in terms of acknowledging womens' sexuality: it's not really in the mentality to provide explicit sexual content with women for women, the mangakas and editors keep the sex mild in order to not distract the readers to much from the plotline and the romance. The explicitness in Yaoi is based on the idea that men are always horny anyway (it's quite sexist in both ways).

Josei is a complex genre because categorization really depends on the prepublishing magazine, which often don't have a defined demography when it targets adult readers, and there is a lot of porosity between Josei and slice of life Seinen... In fact they don't use the categories in the same way as we do in Japan. You could try searching for seinen written by female authors, for example.
There used to be a time where smutty shojos were in fashion (anything SHINJO Mayu and MINAMI Kanan did in the 2000s) but it seems to not be a thing anymore (maybe because the BL industry became bigger and more versatile), and many authors who used to dwell in smut targeted towards girls/women have reverted back to more prudish works.

That being said, the holy grail does exist, it's called Game - Suit no Sukima, lots of sex and an art style that could also suit Yaoi, unfortunately for you it's not being scanlated... You could try to look for raws or chinese scans, if there are any (it's licensed in France if you know any French). The Love Jossie magazine seems to be specializing in smutty Josei but since it's not popular in the scanlation community I guess we're doomed to never get a decent female oriented erotica.
Sefure no Hinkaku gets pretty explicit as well but that's not being scanlated anymore.
You also could check out YOSHIHARA Yuki's works, they're rather sensual and her protagonists are tolerable.
Hoshino Lily's Yumemiru Koto was super sexy and promissing but it will never get a conclusion. As a matter of fact the magazine Manga Erotics F did have a few nice erotica but it's publication ended in 2014 and it was always considered as an "underground" publication.
I'm pretty sure there's a whole female erotica section on the Renta! ebook shop if you have money to spend.
Otherwise, you can try out western erotica, the French and the Italians make wonderful, very classy, erotic graphic novels!

In reality, there is the issue of scanlation teams preferences. Well first, shoujo and josei oriented teams are rarely as proactive as Yaoi oriented teams are, so less releases, and most readers of the genre aren't that much into the smut nowadays, so less chances to see a good smutty josei pop up... Unfortunatley the most visible series are more often the more clichéd, which is why it's so hard to find a good Josei when you don't live in Japan and don't have access to everything that's being published. However there are plenty of jewels out there, even when they're not explicit, Josei is a wonderful genre!

Sorry for the very long post...

I think you should post more often
you know tons