If "boldly" means with courage:
* Timidly
* Fearfully
* Hesitantly
* Cautiously
If "boldly" means confidently and assertively:
* Shyly
* Humbly
* Submissively
* Hesitantly
If "boldly" means daringly and extravagantly:
* Conservatively
* Moderately
* Subtly
* Discreetly
The best opposite will depend on the specific situation and what aspect of "boldly" you want to contrast.