If you really wanna next-level experience, try
Bestia in DTLA. Just look at their yelp reviews. It's a 4.5 rating with thousands of reviews. It's 40min up the 5. Make sure to book a reservation however.
If you want to stick to OC, some fine dining/date experiences are
Cucina Enoteca in Newport or Irvine,
Playground in Santa Ana, or
Mastro's.