What box can I sign so I only get fonts that I can use in public and for commercial use?
On the more options sections it I can choose from: public domain, 100% free, free for personal use, donationware, shareware, demo and unknown.
Ok it is obvious that it is not the free for personal use. But is shareware, public domain and 100% ok to use for commercial use?

If you want to be absolutely sure, you need to contact the author.

Allow me to copy/paste another post I wrote earlier:

Every author has his/her own definition of personal and commercial use, so unfortunately, this is the only thing to do.

Sometimes you can find the information in the .zip file because the author added it (a "readme" text file, a pdf, anything).

If no information is available, you should try to contact the author (website, email address, contact form, social networks, anything).

If you REALLY can't contact the author or if he/she doesn't answer, well at least you tried. If the author gets back to you much later and complains, you can always show the email you sent for example.

Everything is written here: http://www.dafont.com/faq.php#copyright

Shareware is most time free just to test. If you want to use regulary, you have to pay it.
But Drf is true : if you want a reliable answer, contact the author.