Deep Red
Dark Red, Crimson, Rouge, Lipstick
noun
The kanji and the word are exactly the same. That means they share meanings as well.
くれない
べに
A dark red color isn't your favorite color, it is Benny's (べに) favorite color. If you know someone named Benny, it will help.
For the secondary reading, think if you see so much 紅 color (like blood, right?) you know that the person is going to die. You know that there is no cure, aka cure ない (くれない). Get it?
その紅色の花の名前は何ですか？
What’s the name of the dark red flower?