First i chose new comp with the default settings as AE provided me, it was 15fps, but the girl video is 14.285,at the export time AE showed the comp was 15fps so the video would be 15fps so i let AE do that.
And as u mentioned frame blend, i had turned on but i dont know what it works for, i thought like PS it would flatten the video’s layers into one and would be smooth to watch. If anything was wrong i did, then please provide me a default setting on AE for this particular video.