There really isn’t any way to make someone “fear” a dive kick… unless they really suck. It doesn’t do much damage and it’s easy to parry, thus no real “fear” can be projected into your opponent… the trick is to hit them when they don’t expect it. A good way to think of dive kicks is to use them for spacing, helping to move yourself in closer to the opponent, and for cross-ups. Of course, this isn’t to say you shouldn’t use it to attack, but rather you should learn the right time for when you can use them on the offensive. Depending on your opponent, you can use these to your advantage to hit multiple times, or get punished all the time because you’re too predictable. You should get into the habit of using them sparringly and when it’s safe.
You can do something like RH dive kick, Short dive kick to move yourself right infront of your opponent and go for a command grab if you like… but I advise that you DO NOT do this on characters like shotos. It’s easy to see coming, and you can easily be shoryu’d out of it. Things like this have to be used at your descretion, knowing the type of opponent you’re playing. It’s pretty risky, but if it works, it works.
Anyways, what you can do to use the dive kicks up close is to keep your game to the middle of the screen as much as possible. Opponents are going to want to pressure you into the corner, and by how Yun’s runaway game works, you’ll be pushed into the corner quite a few times trying to build up your GJ meter, so you won’t be able to keep the game in the middle at all times. Just do the best you can.
Some examples of using the dive kick up close are using c. short as a tick, followed by a dive kick. The dive kick usually hits or gets blocked in this situation, which will then set you up for another mixup. If your opponent parries it, hey, they’re either parry happy, they knew it was coming (which means you’re abusing the dive kicks too much), or they have some crazy reaction time.
If you keep the fight in the middle, you should be able to dive kick once in a while without being punished so long as you do it quick and unexpectedly, and you don’t dive kick so much throughout the whole match that they just wait there for you to do it. Did that make sense? lol.
Sorry I just got off of school and my explanation may not be sound, but I hope this helps somewhat…
In a nutshell, keep the fight in the middle when you don’t have GJ, use dive kicks sparringly, and you should be safe to use the dive kicks up close.