訳(わけ)だFor that reason, No wonder, As you'd expect, Naturally, Thus, This is why

The phrase はずがない is used when something is seen as hardly possible or highly unlikely to happen, expressing a strong sense of disbelief or denial about something. On the other hand, わけだ is used when explaining or concluding a reason or cause, implying a sense of understanding or realization about why something is a certain way, such as 'no wonder' or 'naturally'.

While both "だけのことはある" and "わけだ" can be translated as "no wonder" or "it's not surprising", they are used in different contexts. "だけのことはある" is typically used to acknowledge the clear display of someone's skill or worth which explains a particular outcome, like, "He's a professional cook, no wonder his meal is delicious!". "わけだ" is generally used when something becomes clear or when a reason is identified, like, "It’s raining, so that's why you came by car." Hence, the first focuses on a recognized ability influencing an outcome while the second is about deducing reasons behind a situation.

The Japanese grammar point わけだ is typically used to draw a conclusion from certain information, implying an "oh, now I understand" feeling. It adds an explanatory note to the statement, often signifying a realization or conclusion. On the other hand, はずだ is majorly used when the speaker believes that something should be the case based on certain knowledge or evidence on hand. It signifies an expectation, assumption, or prediction, not a confirmed fact or realization like わけだ.

Both だけに and わけだ in Japanese express a cause-and-effect relationship, but they are used in slightly different contexts. だけに usually emphasizes the natural result of a certain condition or circumstance, often expressing a sense of expectedness or inevitability about the outcome. On the other hand, わけだ is used when the speaker has observed or found out about a situation or fact, and it shows they've come to understand or make sense of it, often communicating a sense of realization or conclusion about why something is the way it is.

The main difference between these two Japanese grammar points lies in the underlying implication. わけだ focuses on explaining the reason or cause behind a certain situation or condition already known to the speaker, often translating to phrases like "no wonder" or "that's why". On the other hand, ため(に) is used to indicate purpose or objective; it explains the motive of an action or event, often mapped to phrases like "in order to" or "for the sake of".

The grammar point わけだ emphasizes a natural conclusion or reason for something, often in reflection or realization, translating to English phrases such as 'for that reason', 'naturally', or 'no wonder'. On the other hand, ことだ expresses an imperative or strong suggestion, akin to saying someone 'should' or 'ought to' do something in English. Thus, while わけだ provides an explanation or justification, ことだ urges or prescribes a particular action.