Rose and Dagger

The dagger symbolizes bravery and brawn, darkness and lostness.
The rose symbolizes love, joy, redemption and hope.

How the rose and dagger is depicted together influences it's meaning.

If the dagger is pierced into the rose, together it symbolizes betrayal, pain, and the loss of these rose symbolisms such as losing the love of your life.

If the rose is being wrapped around the dagger, it could have two meanings. One, a human who may seem like a nice person or a trust worthy person, but underneath is a menace to society. Or two, the classic opposites attract. Two people of two completely different natures coming together, like the rose and the dagger. One to redeem the other, who is unknown to himself. Like Wenwu and his wife (Marvel), or even the cliché good girl bad guy pairing.

It can also be used as a phrase to describe such a person, or couple, or situation.

"Now that's a rose and dagger relationship," Charles sighed. "Let's see how this ends."
"I should have known he was a rose and dagger," Ryder groaned. "I'm so oblivious, it's painful."