I think it is "If you want me to return the princess, surrender the castle" as you said.
Please note that「娘」could be a young woman or someone's daughter and not necessarily a princess, but I am assuming you already know who that is from the context (that the princess is a young woman that speaker knows about)
「VVVてほしくば」=「VVVてほしければ」= "If [you (...
When we say 分かってくれ and such, we have to use を.
These を can not be replaced with が, so I can at least say 分かる is transitive in these examples, just like English "to understand".
But when can we use 分かる as a transitive verb? It's complicated and I can't explain it well, but you can ...
dictionary.goo.ne.jp explains the differences thusly (written in Japanese):
This is a sentence fragment, not a complete sentence. Since we’re missing the context, the best I can suggest is that this is expressing
for example, were it not me but Hayama
In これが俺ではなく, the くform here of ない lets you know that the speaker is in the midst of expressing a partial idea completed by 葉山なら, but what’s being said about 葉山 has not been ...
Only #2. When it appears in the reduced form, it is always an auxiliary (it is less frequently a main verb after a te-form anyways). This is similar to "I'll" or "I don't" cases in English, which are never main verbs in those forms.
帰っている = is at home / has been back and stays home
帰ってる = is at home
書いてしまう = has accidentally written / ...
と here conveys the idea “at that moment”. Which moment? The one described in the previous sentence.
But it seems you left out some of the following context. I’m guessing but it seems to me that the cat which has been quietly perched on her shoulder now begins to speak.
At any rate, this sort of dramatic use of と is not unusual and gives a sense of immediacy ...
Saying both ようになる and つもりです is fine. They mean different things, so it is not redundant.
But you have to match the subject and the object. 目標は～つもりです literally translates to "The objective intends to ～" or "My purpose is going to ～", which does not make sense because the objective itself does not have a will.
Instead, you have to say ...
These word classes seem to be roughly based on IPA品詞体系. It includes domain-specific abbreviations and rarer classes from archaic Japanese. Some seem to be coined terms to handle minor exceptions rather than standard grammar terms.
副詞可能 seems to be a domain-specific coined abbreviation to me. Here it means "can be used (also) as an adverb" (or &...