o say it never fade, that is wrong. First you have to know, in the dictionary, "omoi wo yoseru" means to fall in love/take a fancy to. Now, to understand what level of "love" it is, you must understand the japanese view of love.
What is equivalent to love in japanese? "Suki", "Koi" and "Ai". Arguably "suki" only equals to "like"... but the japanese usually use the word "daisuki" (really like) when they want to express their feeling to their beloved, so it kinda counts.
Now, basically, Japanese think that Ai > Koi. Its been established many times because Ai is unconditional forever type of love, whether romantically or platonically, while Koi is something that we feel in the beginning, only temporary. When we first fall for someone, we wont be able to say that the love we felt at that time is (ZOMG TRUE LOVE) kind of feeling. Thus, Koi represent that kind of love. Which is why in kanji, first love use Koi instead of Ai. Now...... The most important bit, Ai cannot exist without Koi but Koi can exist without Ai. Why?
Simply ----> You have to fall in love (Koi) first before you can really love (Ai) towards someone.
Thus, the Japanese never say fall in love with "Ai", Instead they use "Koi ni ochiru". They never say I love you with "koi", Instead they use "Aishiteru".
Therefore, "Omoi wo yoseru" (fall in love/take a fancy to), the love in that sentence can only be "koi". Its not true that it wont fade like <3 claim, that the love can never fade.
Even for Rinoa and Squall, its not true. Why? eventually koi will dissapear. Its not meant to last. Why? Koi will either dissapear or turn into another kind of love (Ai). Rinoa and Squall's koi fade and turn into Ai, while Cloud and Tifa's koi simply fade. And lets not forget that "honoka" is used with that phrase. By honoka, it means "slight, faint etc".