Rob Kardashian is a true romantic at heart, turns out ... he pulled out all the traditional stops for his freshly minted fiancee Blac Chyna.
We're told Rob set the mood by covering the room in Chyna's house where he proposed with hundreds of rose petals -- more than 500 roses died in this stunt.
Rob wasn't done ... he adorned the place with enough candles to light up a Justin Bieber concert at Staples.
Blac Chyna and her mom walked into the room with Rob in tow, when he got down on bended knee to pop the question.
Blac Chyna's response ... "Of course, baby! You know I love you!"