Yarinaoshi Reijou wa Ryuutei Heika wo Kouryakuchuu

In both shows, the main heroine dies and goes back in time and falls in love with an enemy from the previous timeline in order to survive her impending death. They both have knowledge of their previous lives in order to figure out how to avoid dying. 

Well here are some similarities and differences of the two . SIMILARITIES: • MC is a princess/duchess • Both died but restarted their lives from childhood (not Isekai) • Both are Avoiding their deaths • Supposed-to-be enemies became their friends/allies • Both are time travel but only that one time DIFFERENCES: • One is pretending to be wise due to previous life experience • One married to change her route away from her death flag • One is more comedic I do recommend both if you haven’t already seen them.  

Both about main character is a girl who is to marry a king. The kings are both seem as evil, cold monsters but in actuality, the king is a kind hearted, misunderstood, lonely man. The girls in both series develops feelings and protects the man as nobody protects them. Lots of romance, cute shoujo 

Both main character girls are reborn in the world and knows what happens in the future. They are forced to marry a man who will ruin them, so the girls ran away to find another man to marry so that they can escape. Turn out the guys they both chose are a "evil" king. They fall in love with each other in both animes and protect them. There is also spiritual being that both girl main character can see and befriends who are associtaed with the king Similar plot. You'll love one another.