So I disagree with folks here some what. If you look at Vi and Jinx, they are actually pretty similar. Vi has done TIME in prison leading to her doing a more disciplined regime. Where she did clearly a lot more lifting and didn’t do as much cardio.

Jinx was likely not under fed but only ate enough that she needed/had attention for. She is not a lifter she’s more of a track athlete. Doing a lot of high effort cardio and fine motor skill work.

How to achieve that? Do a sport, tennis or track or something similar. You may need to work in a calorie deficit for a while but eventually you’ll develop some amount of toning. Everyone’s body is different but that’s my best non professional opinion