thumb|right|300px|Believix transformation thumb|300px|right|Roxy's Believix Believix is the new transformation the girls get in Season 4. It is the transformation after Enchantix, but due to the fact the girls fly back to Magix at the end of the season, it is said not to be the final form.
For a Fairy to earn her Believix form, she has to make people believe in fairies and magic, thus Believix can only be earned on Earth or somewhere where people do not believe in magic. Believix gets stronger when more people believe in magic, which means that if a fairy does not convince people to believe in fairies and magic, her powers will weaken.
The Believix comes with four types of wings: the normal wings, and than the fairy have Speedix, Zoomix and Tracix. The Winx Club earn their Believix in Season 4 episode 6 because Roxy believes in them. Roxy earns her Believix in season 4 episode 12 because Artu was seriously injured, forcing a transformation out of sheer will, like Bloom when she earned her Enchantix. Roxy's Believix is presumably incomplete because she has never used her Speedix, Zoomix or Tracix wings.
In Episode 4x19 the Winx earn another new power called Sophix, this is one of the Gifts of Destiny (the Gift of Knowledge) and give the Winx Club flower and plant powers akin to Flora's and the ability to be in complete harmony with nature. The Second Gift (the Gift of Courage) boosts their courage and they earn Lovix, a transformation that gives them ice powers. The Third Gift (the Gift of Darkness) did not give the girls a new transformation, it was instead a power to bring someone dead back to life, but they could use it only one time. A question arose when Stella first appeared in episode 1 of Season 1. She got Bloom and her family to believe in magic but did not earn her Believix. This presumably means in most normal conditons a fairy must have her Enchantix to earn her complete Believix, or the person that believes in them needs to be an Earth fairy, or that the have to intentionally try to make people believe in magic (but at the beginning of the same episode, Bloom herself said that she still believed in fairies when her mother told her to stop reading fairy tales, so Stella would not have earned the Believix as Bloom already believed in magic).
With the Believix, a fairy has the power to reach out to someone's heart and help people overcome their bad habits or weaknesses. Every fairy has a different type of this power:
Bloom: Force' of Life
Stella: Light of Dawn
Flora: Breath of the World
Musa: Splendid Heart
Tecna: Gem of the Mind
Layla: Spirit of Courage
Roxy: None (however, it can be assumed that she has one and simply hasn't used it)
Gallery of Attacks
Every girl has a special effect added to their attacks, which is different for every girl and has something to do with their main power.
Gallery of Believix Powers
It is questioned whether this is the final form; the girls were seen at the end of Season 4 flying back to Magix in Enchantix form. Some say it is because pictures and snapshots of the second movie show the girls in Believix form.
However, in the series, when the Winx girls first arrived to Earth, Miss Faragonda told them that the final fairy form is Enchantix, but that there are many other, higher, levels of transformation with powers which are different than those of Enchantix, and are gained in specific situations, in the case of Believix it is by making people who don't believe in magic start believing in it, and that the fairies can then use these powers instead of their Enchantix powers. This would probably suggest that the normal final fairy form is effectively Enchantix, and that Believix is in fact a higher level transformation, above the normal fairy levels, and that the fairies who have accessed Believix level have the option of using either Enchantix, Believix or any other higher fairy level (Faragonda said that there were many others) as they wish, which explains why the girls used Believix instead of Enchantix in the second movie.
Something else which suggests that Enchantix is the final form is that students at Alfea undergo a three-year course, the first one to control their standard fairy forms (their Winx in the 4KIDS version), the second one to earn their Charmix, and the third one to get their Enchantix. Believix is not studied at Alfea, as it is not a normal fairy level, and not anyone can earn Believix powers (so far in the series almost the whole Universe, Earth included after season 4, believes in magic, and therefore it is very difficult, and nearly impossible, to earn Believix anymore, atleast there still remains people on Earth on on some other planet who refuse to believe in magic). At the end of season 4, when the Winx fly away, their return to Enchantix possibly sets the scene for the new higher level transformation to come in season 5, as these higher level transformations are mostly supposed to be magical evolutions from Enchantix, which remains the base transformation from which these powers can be accessed to (these higher level transformations themselves may have their own evolutions, in the case of Sophix and Lovix for Believix).
The fairies clothing is more casual themed in this form than other forms. The fact that it looks this way could be since they obtained this form on Earth and that they are styled similarly to Earth clothing. It mainly consists of stylized skirts and/or capris with with knee high socks and boots or sandals (similar to what they wear regularly). The wings show images that could either relate to the power or power theme (Flora's wings have a repeating flower pattern, Stella has a star pattern, and Bloom with hearts). They all also obtain a type of wrist accesory, like Tecna with fingerless gloves and Bloom with smaller versions of her arm gloves.