If the dialogue doesn't match the audio (which can happen if the BluRay rip has a different frame rate than the subtitle was made for):

To ensure the subtitle works automatically with your video file:

If you are looking for subtitles for the 1998 thriller specifically for the 720p BluRay x264 release, here are the most reliable ways to find and use them: Where to Find the Subtitle File

Search for "Disturbing Behavior 1998" and look for entries tagged with "BluRay" or "x264." These are usually perfectly synced for high-definition rips.

Press G to delay the subtitle or H to speed it up by 50ms increments.