How do I fix slow motion issues in Final Cut Pro X?

the one on the right is from fcpx and the one on the left is from premier, My problem is that i couldnt find an solution for the slow motion, in premier i can easily interpret footage from 59.94 to 29.97 and then speed up the section i dont want to be slow down without getting those "double fade" around the kite when working in fcpx i couldnt find a way to do that doesnt metter with slow motion method i used i got those "double fade" look on the kite itself how can i fix it? i really prefer fcpx over premier but cant have those artifical stuff specially when i shoot intentionally on 60 frames in order to slow down the footage.

i also tried compounding the clip didnt help, why there isnt any way to interpret the footage in the browser before putting it on the timeline

[Re-Titled by Moderator]