1. Is it possible for me to sell this game
2. (get sponsored)
3. for any portal
4. for at least 500euros(560US dollars)?
5. I see that in our day there lots of great flash games that's why my game is most likely is unsalable

1. Anything is possible*. Don't ask "is it possible." Ask, rather, about likelihood (if likelihood
is useful information for you).
2. Wait, which are you asking? Sale? Or sponsorship? Those are two different things. And what
exactly do you mean by sponsorship?
3. So you want a portal to host your game, and you want them to give you a flat amount of money for
the privilege? That seems unlikely.
4. Your request is very specific. Maybe somebody else can talk to you about typical amounts.
5. Good, you're talking about likelihood now. I imagine it's likely some portal will take your game,
but maybe not for money and maybe not for as much as you want. There's another option, you know -
you could improve your game, and you could make another (better) one.

*Actually, there are 2 things that are not possible: time travel to the past, and the Star Trek
holodeck.

Also, I moved this to the Business forum, because you're talking about the business end (you're
no longer managing a project).

Anything is possible*. Don't ask "is it possible." Ask, rather, about likelihood (if likelihood is useful information for you).

Think is the perfect summary if it was the only question that was asked.

Honestly, from my game release experience it is best to find the one project you love and work to bring it out to the world stage. Whether that is to the App Store or something your friends share, working to get a project complete is the greatest goal. Once you have a complete game, then find how to promote it and get it into the hands of your intended audience.

It wouldn't be a problem if i just gave this game some hours, but ohhhh noooo i gave it some months...

Is it possible for me to sell this game(get sponsored) for any portal for at least 500euros(560US dollars)?

Is that full time work, or just in your evenings / weekends?

If you put it on the Apple/Android app store for $0.99 you'd have to sell about 1000 copies to make the money you want, which honestly... is not likely. If you want to run a successful business, you don't just need great game development skills, but also business management/strategy and marketing skills. Even with all of that, most games are not financially successful.

Making games as a business is hard.

Converted to my local currency, 500 euros is enough money to hire a programmer for between 1 to 5 days, depending on skill level. Most games take a lot longer than that to make, so they need to collect a lot more revenue than that. The people who are running successful games businesses -- even making simple mobile games -- often require their games to make $100k or more to pay off the expenses incurred in making it.

Honestly, if you're not ready to start a legitimate business like this, you should avoid disappointment by treating your game development as a fun hobby, not as a profit-making machine.