Will a sigma ef-430 ST work with my Nikon d7100?

Will a sigma ef-430 ST work with my Nikon d7100? - 1

"This flash was designed for dedicated OTF TTL use. It is not compatible with the type pre-flash TTL found on DSLRs. Manual mode may work on a DSLR, but in some cases, you may have to isolate or remove the "extra" TTL control pins from the hot-foot to stop the camera from being confused by the legacy OTF TTL protocol." -- http://dpanswers.com

Here are two other links I found using my favorite search engine.

You can do the same

The flash would surely work in Auto mode with your camera in manual mode. Further than that, you should investigate deeper on the TTL compatibility of that flash to your camera. With Nikon, TTL is not enough. Your camera already uses iTTL.