When it comes to likelihood of confusion refusals, there's no one-size-fits-all answer as to how hard they are to overcome. Your chances will depend on multiple factors, including:
- Your mark and the other identified mark,
- Your and the other party's goods and services,
- Your and the other party's sales channels,
- Who the other party is - whether it's an individual or a company, their size, presence in the market, etc.
Therefore, if you've received a likelihood of confusion refusal from the USPTO, it's best to seek the help of a qualified trademark attorney who can read the examiner's reasoning in the office action, consider these and other factors and recommend appropriate steps for you to take.