Dwight handed her a bouquet of small, yellow flowers. Jennifer buried her nose into them and said, “They smell heavenly. What are they?
“They’re yellow jasmine. I chose them because they are a symbol of grace and elegance.” He grinned. She thought it was the most romantic thing he’d ever said, until he added, “Like me,” and then chuckled. Always sarcastic! she thought.
The elements of humor are there, but the beats and delivery are off. I would try something more like this-
Jenn buried her nose in the bouquet of small yellow flowers "Dwight, they're beautiful!- and they smell wonderful. What are they?"
"Yellow Jasmine. They're a symbol of elegance and grace. Like me!"
"You're so full of yourself." But she did smile. A little.