What it means
だけに expresses a strong causal relationship: precisely because something is true, a result, evaluation, or reaction is especially understandable or expected. It often highlights a reason that makes the following situation more convincing, significant, or emotionally meaningful. It can attach to a plain verb or i-adjective, directly to a noun, and with a na-adjective it follows な.
Usage note
With nouns, だけに attaches directly, as in 専門家だけに; な is not used. With na-adjectives, な is required before だけに, as in 慎重なだけに. The clause before だけに is normally in plain form, even when the overall sentence is polite.
How to use it
彼は専門家だけに、説明が明快です。
Precisely because he is a specialist, his explanation is clear.
彼は慎重なだけに、確認に時間をかけます。
Precisely because he is cautious, he spends time checking.
その試験は厳しいだけに、合格した喜びが大きいです。
Precisely because the examination is difficult, the joy of passing is great.
彼は毎日努力しているだけに、成果を期待しています。
Precisely because he works hard every day, he expects results.
彼は専門家だけに、説明が明快だ。
Precisely because he is a specialist, his explanation is clear.
彼は慎重なだけに、確認に時間をかける。
Precisely because he is cautious, he spends time checking.
その試験は厳しいだけに、合格した喜びが大きい。
Precisely because the examination is difficult, the joy of passing is great.
彼は毎日努力しているだけに、成果を期待している。
Precisely because he works hard every day, he expects results.
Example sentences
長年この町で暮らしてきただけに、駅前の再開発には複雑な思いがあります。
Precisely because I have lived in this town for many years, I have mixed feelings about the redevelopment in front of the station.
彼は経験豊富な専門家だけに、複雑な機械の故障もすぐに見抜いた。
Precisely because he is an experienced specialist, he quickly identified the malfunction in the complicated machine as well.