The Duchess's Contract Marriage

To leave the nunhood to avenge her parents by killing the tyrant king, Rubiana swears to devote her firstborn child to God. After all is done, she's ready to fulfill her oath, except... She doesn't have a husband! Enter Louis, the only descendant of the late king and rival to the current ruler. He's got a proposal for Rubiana: he'll help her bear a child if they marry and she assures his safety. But with danger around every corner, will they both be able to hold up their end of the deal?