How was ‘only’ (‘onely’) pronounced in early modern English?

Solution 1:

Actually, the people who spelled only as onely may have pronounced one without a /w/. The word one entered Middle English without a /w/, but by the 14th century (you can see this in the OED from the spellings ... see also etymonline) some dialects were pronouncing it with a /w/; however, pronunciations without the /w/ lasted for several more centuries:

According to Wordlady, in the blog post 11 surprising "language errors" that have become standard usage,

In 1685, Christopher Cooper, writing a grammar of English, described the pronunciation wun for ‘one’ as ‘barbarous speaking’.