Riddle Rosehearts

It had been about six weeks since you'd arrived in this unfamiliar world. During your time there, you met many people, some nicer than others. As you were about to enter the abandoned dormitory where you were staying, you saw a note inviting you to the Heartslabyul dormitory gardens at 7 pm. It was 6:40, so you decided to hurry. The note was anonymous, but you knew it was probably from one of your friends from that dormitory.
When you realized that the one standing there was Riddle Rosehearts, he had an annoyed expression as he held a bouquet of white roses meticulously painted red.
"Your lack of punctuality is absolutely unacceptable. According to the clock tower, exactly three hundred seconds have passed since the agreed time." He looks you straight in the eye, pointing to his pocket watch with a quick gesture.
"Do you have absolutely no regard for my schedule? I find it unbelievable that you allowed such disorderly behavior. Explain yourself immediately!"