Regarding when to use daisuki, suki, suki desu, aishiteru, and koishiteru

[Kadmos]

I know that *daisuki, suki, and suki desu all translate to "like", "really like", or "love". While I know these words can be used to describe something you like, from a love standpoint (eros, agape, storge, philia), what are the differences between suki and su? That is, when would you say each word?

ﾂ'O ia mau n? (Daisuki, Aishiteru and Koishiteru all have different meanings.)

Daisuki, Aishiteru and Koishiteru all have different meanings.

I can't stress that enough.

Koishiteru ﾂ（窶氾ｶ窶堋ｵ窶堙??堙ｩﾂ。)- A term used by people to express that they have feelings for someone. It basically means that, ﾂ"I love someone.ﾂ"

Aishiteru (ﾋ?､窶堋ｵ窶堙??堙ｩﾂ。)- A term used by married people or those in a very committed relationship. It's still heard a lot in J-pop, dramas or by those who share such strong feelings for each other. Which means, "I love you."

Daisuki (窶堋ｾ窶堋｢窶堋ｷ窶堋ｫﾂ。)-A term used mostly by teens to confess their feelings towards a crush. This term is often confused by many people who watch Japanese dramas because most dramas focus on highschoolers who want to express their feelings to their crush. It doesn't translate to, ﾂ"I love you.ﾂ" No. This word translates more along the lines of, ﾂ"I like you a lot.ﾂ" It's just a greater form of suki (窶堋ｷ窶堋ｫ) which means like. Placing dai (窶堋ｾ窶堋｢) in front of suki (窶堋ｷ窶堋ｫ) just shows how much you like it

My questions on the suki words are also being asked about these 2 words.

Related: I understand aishiteru to be used when people are on the soul mate level. With this, how is it meaning "I love you" different than koishiteru's meaning of "I love someone" (besides the lack of you)?

In Naruto Shippuden episode 339, Itachi the older brother says "aishiteru" to Sasuke the younger brother. I don't understand why he used that word because I thought that word was almost exclusively used in romance.

*While quoted Tumblr link does explain daisuki, I still don't known when you would use that over the 2 suki words and vice versa.

 

[nekojita]

Koi is specifically romantic, the others are not (although will be taken that way if used in the context of a potential romantic partner.)

Aisuru can be used towards family members or even things that aren't people (love for your country, for example).

(Dai)suki can be used to talk about liking a wide range of things. (desu is about politness and does not change the meaning.) I like cats, I love this song, etc.

 

[devilzempire]

Suki means like, although in some cases it is translated as love. It can be used while describing something friendly and also while describing something romantic, it depends on what you are saying. It is pronounced as Ski.
Dai suki means the same thing as just suki but with the word lot added to it. It is pronounced as daiski.
Aishiteru is a strong word. It means love. It is usually said to someone that you are in a serious relationship with. If you are describing an object then it signifies that you have an undying love for it.
Koishiteru also means love but it express a greater degree of love than aishiteru. It said to the person who is considered your soulmate.