Both took place in the Republican era of war. Female lead was smart and honest with her feelings the whole time. Male lead fell in love with the lady first and expresses his love for her. Love and hate was the relationship but they gradually learn to appreciate life.
It's almost the exact same story, despite a completely different tone (and time period) - being more accurate to the book, Love in the Rain is darker and more melodramatic than Romance in the Rain.
These are so similar that it could be called remake but in a different cultural setting
Both are set in China Republican era, the Sino-Japanese war. Stories that focus on the relationships surrounding a prominent family during the time. Both have obsessive/stubborn main leads and love triangles.
some main characters of Princess Pearl are reunited again in Romance in the Rain. it is just lovely to see them acting together and thus the writer of Princess Pearl is also the one who writes RITR. RITR is a story of tragedy, comedy, life struggling, and eternal romance.
Both have the similiar time story: during the japanese invasion in china. Battle of Changsha has less romance than romance in the rain, but with more family, and more war actions.