Yeah, we have to assume that Peach is generally as caught and well-captured and bound as Samus is. Samus is simply more capable of handling the sitaution; both her and Peach are athletic, but one has combat training and likely experience with escape. The princess, while having experience, likely does not have this kind of knowledge to escape bindings.
Also, it would be fair to assume that Peach getting captured would be distressing. Giant evil turtle trying to take over your world and hurt your hero/friend/potential boyfriend who is there to help you? Gotta say that I'd be pretty distressed too, if the gender roles were reversed or even if the people were reversed like they are here. Also, struggling and squirming in ropes can be rather tense.