I hope you did not experience anything as sad today.
今日そんな悲しさをなければと希望してます。
今日そんな悲しいことがなければといいな。
今日そんな悲しさをなかったらといいな。
今日そんな悲しいことがなかったと希望してます。
Are any of these close to what I am trying to say? To give context I found a mikan ice cream today and was really happy but it turned out to be really bad. So I was talking with a girl and wanted to say that I hoped nothing as said has happened to her. Is there maybe a better way of saying this than I am trying to use?
Thank you in advance.
Caution: It is easy to "translate" things into Japanese, but whether or not that translated phrase/sentence would actually be uttered/written by a native Japanese speaker somewhere is a totally different matter.
First, my comment on each of your attempts.
今日{きょう}そんな悲{かな}しさをなければと希望{きぼう}してます。
Ungrammatical for using 「を」. 「ない」 is an adjective, so you cannot use an 「を」 right in front of it.
今日そんな悲しいことがなければといいな。
Ungrammatical for using 「と」 there. You can say 「ないといい」, but not 「なければといい」. That 「と」 needs to be dropped.
今日そんな悲しさをなかったらといいな。
Ungrammatical for the same reason as the first sentence. You might want to review the particle 「を」. You may have been over-using it.
今日そんな悲しいことがなかったと希望してます。
Looks pretty good as far as grammar. We just do not use 「希望する」 nearly as often as English-speakers use "to hope". Remember if you can that 「希望する」is a bigger word than "to hope".
My own TL's:
「こんな悲しい出来事{できごと}が、今日{きょう}君{きみ}には起{お}こらなかったことを願{ねが}ってる。」
「こんな悲しいことが、今日、少{すく}なくとも君には起きなかったことを願ってる。」
「こんな悲しい出来事が、今日君にはなかったことを祈{いの}って・・」
