Hardly/unlikely - what is true?
barely service particle expresses doubt, and has only one standard spelling option - "barely", in two words without a hyphen
The particle "barely" also exists - and is recorded in all authorized dictionaries. But labeled as "talk" or "outdated". That is, in colloquial speech this combination can be used, in principle, but since we are talking about literary and literary speech, it is better to use a more traditional version and write "barely".
Just to be safe: with "if" the word "unlikely", if at all, is also written separately.
grammar
๐ฟ Russian proverbs