this sentence should be like, because you dont know what the other part of the sentence would be.
Matthew, in this context, what is the difference between "as" and "like"?
Here the correct answer is clearly "as" because it is typically followed by a subject+verb construction whereas "like" can be used when there's no verb. Ex: He won't succeed like his sister
@leberkez: ?? It's most certainly "like" in this sentence. You can say "He won't succeed, as she will make sure of it.", but in the context presented, he is being compared to her, therefore 'like' is used.
Honestly, I think "like" is as good as "as" here, but "as if" is just plain wrong. The poll didn't make that an option.