Happy Ending for the Time Limited Villainess

Happy Ending for the Time-Limited Villainess My reputation was the worst. The Demon Lord said he’ll save my body if I get married happily, but the condition is mortifying. I have to get married to the man I’ve had an unrequited crush on, Duke Detroit. I said I’ll do anything in order to get married, but I don’t know what a “happy marriage” is… Will I be able to survive?