Daarin is the best way to say 'my darling' in Japanese. Since the Japanese language doesn't really have any native
Koi. Koi (恋 / こい) is often interpreted as 'romantic love' or 'passionate love'. Normally, it has a nuance of young love, or the kind of love that just began blossoming. Like a crush!
Senpai is often used in the English in the expression “notice me senpai” and its variants. Originally this was used in the context of a person hoping a crush or someone they admire will pay attention to them, but it has more broadly been used online in reference to famous people acknowledging a fan's existence.
Koibito (恋人 / こいびと) is the Japanese word for 'sweetheart' or 'lover'. It consists of the characters for love (恋) and person (人). It can be used for a girlfriend or boyfriend, or even husband or wife.
Chan, the childish version of san, refers to children and girls. The change from “s” sound to “ch” is considered cute in Japanese. Like for kun, friends and lovers can also address each other with this honorific.
You can address a woman or girl by -kun, but it's usually used by women to men. They might call their boyfriends or spouses -くん to show affection, like -ちゃん. Likewise, women often call children, especially boys, by -くん.
ちゃん/-chan
It is not appropriate in a work environment, but can be a nice, cute nickname for friends or romantic partners. It's typically used for young women you're close with, children, babies and animals, and can even be used for beloved older relatives, like a grandmother.
Some guys go the "classic" route with names like "angel," "darling," and "sweetheart"; some prefer food-inspired nicknames, like "cookie" and "cupcake"; and some straight-up worship their partners with loving names like "queen," "goddess," and "light of my life."
No, senpai means “person who is my senior in school/work/other field but isn't my boss”. Ie. People a year or two above you in school would be called senpai.
Ara Ara is a Japanese expression, a word you say when you are moved or surprised (A term that repeats the interjection “Ara” twice) and means oh dear or oh my in English, depending on the situation. I'm sure you've seen scenes where women use “Ara Ara” in anime, but it's also used in real life.
Baka is a Japanese word that means “crazy,” “foolish,” or downright “stupid.” It can also be used as a noun for “a fool” or “a crazy or stupid person.” Anime and manga fans in the West have adopted the use of baka as a (usually joking) insult.
Nevertheless, for a confession, the most basic and widespread phrase is “suki desu” (好きです, I like you), often followed up by “tsukiatte kudasai” (付き合ってください, please go out with me).
“Daisuki desu” means to really like or love something, so this has a similar effect as “suki desu”. For example, if you are confessing your feelings for someone, you might say: Suki desu! Tsukiatte kudasai.
Kareshi (彼氏 / かれし) is the most commonly used word for 'boyfriend' in Japanese.
Wwww is the Japanese equivalent of the English hahahaha, used to express laughter online and in text message.
If you're in a committed relationship, you can bump it up a notch to 大好きだよ (daisuki da yo), which is “I really like/love you.” The word daisuki in Japanese combines the kanji for “big” (大) and “like” 好き (like) to mean you have strong affection or interest in something. But daisuki can be used to say “I love” …
More commonly used is 好きだよ(sukidayo), which literally means “I like you”.
For students, the term is usually xuézhǎng/xuéjiě (學長/姐, more common in Taiwan) or shīxiōng/shījiě (师兄/姐, Mainland China) for male and female senpai, respectively, and xuédì/xuémèi (學弟/妹, Taiwan) or shīdì/shīmèi (师弟/妹, Mainland China) for male and female kohai, respectively.
You may know it as the senpai-kouhai system. Senpai (先輩 / せんぱい) means one's superior. The opposite of senpai is kouhai (後輩 / こうはい), one's junior, a younger person or colleague who has little experience.
In Japanese, "~ san （～さん）" is a title of respect added to a name. It can be used with both male and female names, and with either surnames or given names. It can also be attached to the name of occupations and titles.