Do i really need TTL for do portraits ? I'm only need it for portraits not for nothing more
(Portraits outdoors) or with a manual it's enough?
TTL is not required. A lot of users even prefer manual flash, especially in fixed studio situations. But, they have learned how to do it. You can learn if you don't know now, but it is sort of a big step.
With the TTL flash, its TTL BL mode is point&shoot, including fill flash in bright sun. Easy way in bright sun, just set the camera to P mode, and the TTL BL flash is point and shoot, and the results are usually very good (exposure wise, and fill wise). You can change the compensation to make small changes.
With a manual flash, you have to first set the flash power level to be the right level to give the results you want. TTL meters it, but this does not happen with manual flash. Poor level choices may be too weak to be noticeable, or to have effect, or too strong overexposing the subject, etc. You can readjust the manual power by trial and error, until you get the result you want. Repeating this effort again in every new situation.
I am suggesting it is pretty nice to have the choices.