に対（たい）する and
に対（たい）して are two grammar patterns in Japanese that are regularly used to show when (B) is ‘opposed to’ or ‘in contrast with’ (A). 対（たい）する itself is a verb meaning ‘to oppose’. Although this feeling of ‘opposition’ may be negative, in most circumstances, it just means ‘toward’ in the sense of targeting something.
に対（たい）する will be followed directly by a second noun, while
に対（たい）して creates a pause in the sentence, before (B) will be explained in the second half of that sentence.
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君（きみ）に対（たい）する気持（きも）ちは一生（いっしょう）変（か）わらない。
My feelings toward you will never change.
私（わたし）は店員（てんいん）に対（たい）する態度（たいど）が悪（わる）い人（ひと）が苦手（にがて）です。
I don't like people who have a bad attitude towards store employees. (People who target their bad attitude at store employees)
ああいう風（ふう）に、先輩（せんぱい）に対（たい）してタメ口（ぐち）を使（つか）うのは良（よ）くないと思（おも）うよ。
I don't think it is best to talk to a senpai using casual speech in that manner. (Talking casually toward a senior)
何（なん）でいつも私（わたし）に対（たい）してそういう酷（ひど）いことを言（い）うの？
Why do you always say mean things like that to me? (With me as the target)
Compared to
に関（かん）して (another structure used to show how things ‘relate’ to each other),
に対（たい）して focuses on (A) and (B) equally, explaining how those things interact, compare, or contrast each other.
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このプロジェクトに関（かん）して質問（しつもん）がある方（かた）は私（わたし）に直接（ちょくせつ）電話（でんわ）をしてください。
If you have any questions concerning this project, please give me a call directly. (Questions in relation to this project)
私（わたし）はサッカーが好（す）きなのに対（たい）して、彼（かれ）はバドミントンが好（す）き。
In contrast to me liking soccer, he likes badminton. (Opposed to me who likes soccer)
As
に対（たい）して strongly contrasts (A) and (B), this grammar structure will often be used to express differences between two things. This is very similar to ‘whereas’ in English.
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マサミは難（むずか）しい本（ほん）を読（よ）んだのに対（たい）して、カスミは簡単（かんたん）な本（ほん）を読（よ）んだ。
Masami read a difficult book, whereas Kasumi read an easy book.
彼（かれ）の仕事（しごと）は楽（らく）なのに対（たい）して、僕（ぼく）の仕事（しごと）はものすごく大変（たいへん）。
His job is carefree, whereas my job is very difficult.