Wow, you really are a moron.
Let's give another example, one more exaggerated.
Imagine that the suit would be unscatched after a Planet lvl attack (an attack powerfull enough to destroy a planet, Earth size let's say) and Sanji has Mountain lvl durability (durability to take an attack powerfull enough to destroy a mountain).
Now, let's say someone with Moon lvl AP hits, punches him, what will happen?
-The suit would be intact, no damage. Since Planet lvl durability > Moon lvl AP
-Sanji inside the suit would remain as a pool of blood. Yeah, literally, the suit would only have blood inside. Or maybe no, even blood would not remain. The blood maybe would get evaporated entirely!
Since Moon lvl AP >>>>>>> Mountain durability
Why this would happen? Cause the suit are "clothes", a flexible material. When the guy with that punch hits Sanji's suit, the cloth of the suit would stick to Sanji's body, the punch would push it against his body, and the impact/energy of it will travel through it, so Sanji would took the AP of that punch.
Same behavior/working/mechanics as the example I already posted.
...
Yes.
Sanji's durability prevented it. King has no enough AP for that. He was cocky and arrogant and he got slapped in the face instead.