Kokoro's voice effect

Hello all /o/.
Someone knows how to have this voice effect in ココロ (kokoro) please? °°
I didn't find anything about it >_<.
I don't want to use Autotune because it sounds sooo weird OO. Just need something like this: https://www.youtube.com/watch?v=MbClyagwDIU or on Sumire cover please ^w^.

Thank you

Autotune works well, but when you apply autotune, you have to be very careful on identifying the pitches of each word owo...
Cause if you don't hit the right note, or hit half of it, Autotune modifies it by lowering it or putting it in a higher note oAo!
From my... not very previous experiences, xD when you sing with autotune, you have to do the work for autotune, and not autotune do the the work for you owo!
Hope that helped oAo!