anime/light novel : hibike euphonium
Daisuki - Literally "I like you a lot." This is the most commonly used one, but as with every word in Japanese it is very contextual so it can be used among friends as well as in a romantic context. 好き = I like you, but that's a bit more ambiguous so if you were saying "I love you" I think you'd add the 大.
These two are considered kind of cheesy and I don't think they're very widely used but they do exist - 愛してる "aishiteru" and 恋してる "koishiteru" (You would add よ in conversation if you were a guy and わ for a girl.) These are more for a very serious relationship where you want to say "I'm in love with you." Imply commitment and romantic love , whereas "daisuki" is more casual and ambiguous.
qotd : name ONE anime character that you love?
aotd : JUUZOU
Credit: @animelogics --- Follow @animecart