In both dramas there is an adorable leading lady and an equally adorable mother of the leading man. The mother is willing to scheme to try to get the couple to realize and admit that they like each other.
Itazura na Kiss' leading man is the typical cliche smart handsome Jerk, and he does NOT want to admit that he likes the girl.
My Mr. Mermaid's leading man is dedicated to his sport but kind and sweet. He seems quite smitten with the leading lady, right away, although, he keeps on telling everyone that they are just friends.
Itazura na Kiss is based on a manga and there were versions made in Taiwan, Korea, Japan, Thailand, and China... I loved them all. However, if you do not like going through all of those episodes, that make it seem like the girl is chasing a guy who is just not that into her, try Kiss Me(the Thai version) first. In that version, it is apparent, very early on that he has a soft spot for her, compared to the rest.