"A blessing in disguise"
I wanted to go to the movies but my car broke down. It was a blessing in disguise because the move was cancelled.
3 Answers
You can find this idiom in our phrasebook, blessing in disguise.
Look it up, and try to use it in your sentence.
A better example is,
I wanted to go to the movies but my car broke down. It was a blessing in disguise because a fire broke out in the movie theatre and many people were injured.
From TheFreeDictionary.com:
be a blessing in disguise
to be something which has a good effect, although at first it seemed that it would be bad or not lucky Losing my job turned out to be a blessing in disguise because it forced me to think carefully about my future.
Actually, to be effective, "a blessing in disguise" should carry both the notion of something strongly desireable (like buying the winning lottery ticket) which one fails to obtain/have/achieve --- to one's great good fortune (as the person who bought it was 1. mugged for it, 2. had to spend months with the police to prove it was his & to testify against the mugger, 3. was besieged by friends, relatives, strangers & con-artists all hoping for a share, 4. his children were kidnapped & held for ransom and MORE
). It should not be used for slight or minor coincidences.