WARNING: The following contains spoilers for Episode 5 of The Genius Prince’s Guide to Raising a Nation Out of Debt, "A Diabolical Scheme," now streaming on Funimation.
Prince Wein Salema Arbalest and Princess Lowellmina "Lowa" of Earthworld are truly two birds of a feather. From a young age, they were both diabolical schemers and had quite a number of exploits under their belts when they were just students at the Academy. Years later, Lowa shows up in the kingdom of Natra and surprises both Wein and Ninym Ralei with an unexpected marriage proposal. The bigger surprise for them both is that they've been friends with Lowa without knowing she was the imperial princess of Earthworld the whole time.
Since learning Lowa's secret, Wein suspected there was more to Lowa's marriage proposal than politics and correctly assessed that Lowa is trying to accomplish two things: first, she wants to become Empress of Earthworld with backing from another kingdom -- in this case, Natra, which recently defeated the more powerful Marden kingdom. Second, Lowa wants to stop a rebellion from happening and avoid being roped into a political marriage with Gerard Antgatal, whose father, the Marquess Grenache, is known to be a tyrant.
By understanding Lowa's motivations, Wein attempts to circumvent her marriage proposal by announcing her presence in Natra to Gerard in a letter. This prompts Gerard to make a hasty trip to Natra in order to claim Lowa from himself -- a detail Wein is counting on. Unfortunately for Wein, Lowa also intends to use Gerard as a pawn to back him into a corner, and the two old school friends play a mental chess game with each other in Gerard's presence. Their antics unwittingly lead Gerard to his accidental death, which puts them both in a compromising situation with the Marquess Grenache.
After the epic fiasco of Wein and Lowa’s fatal scheming, both monarchs of different kingdoms work together to unscrew the mess they get unwittingly themselves into in Episode 5. They end up killing two birds with one stone by making the Marquess Grenache aware of the rebellion that's about to take place and attempt to pin the whole thing on the deceased Gerard to try and make it look like a usurpation. The Marquess is unconvinced and unwittingly falls into both Wein and Lowa's trap, just as they planned. They also prevent the rebels from destroying evidence inside the Marquess's palace and draw them out into the open before they can carry their plans further.
With both the Marquess and rebellion exposed, the Marquess has no choice but to surrender to Lowa and Wein. With the danger of the rebellion and the Marquess' tyranny averted, for now, Lowa calls off her marriage proposal to Wein. While Lowa intends to leave quietly, Ninym catches on to the fact that there was more to Lowa's marriage proposal than just the threat of a rebellion and her desire to become empress; Lowa is in love with Wein.
Lowa unconvincingly denies that this is the case, but her reactions give her true feelings away. When Ninym remains unconvinced by her "explanations" of her motivations, Lowa finally admits she's romantically interested in Wein and asks her if she's really that easy to read. Ninym admits that she's been aware of Lowa's feelings for Wein since they were students at the Academy. This actually makes sense, as Lowa had asked Wein much earlier on if he would help her advance her goals. Even as a student, Wein declined to help Lowa in any capacity, except by force, which she accepted as a challenge at the time. When she finally decided to honor that challenge years later, it was with a surprise marriage proposal.
While Lowa seems to acknowledge that her love is unrequited, and seems to be aware of Wein's feelings for Ninym, she indicates that she wants to be a part of his life again. As such, she sets out to become Empress of Earthworld through her own efforts and as a way of making herself worthy of Wein. Although Lowa doesn't explicitly acknowledge that she'll attempt to court Wein, at the same time, she hasn't indicated that she's giving up her love. More than likely, she's now motivated to earn it, potentially setting herself up as a rival for Ninym, who also loves Wein romantically.
