N2
つもりで
With the intention of doing, Instead of..., Act as if or pretend, Believing that..., Thinking that...
冗談のつもりで言っただけなのに、相手を傷付けてしまった。
Despite saying it with the intention of making a joke, I ended up hurting their feelings.
Explanation
「つもりで」 has 4 uses
1Acting as if you were
Doing something in the frame of mind of being someone or something: 「プロのつもりで練習する」 (practise as if you were a pro). Often after 「Noun+の」 or 「〜になった」.
今度は、主人公になったつもりで読んでみてください。
Next, try reading it as if you were the main character.
パーティーでダンサーになったつもりで、みんなの前で踊った。
At a party, I danced in front of everybody, as if I was a dancer.
2Treating it as done
After the た-form: you treat something you did not do as already done, and do something else instead: 「旅行に行ったつもりで、お金を貯金した」 (I saved the money as if I had gone on the trip).
外食したつもりで、その分のお金を貯金した。
I put the money aside as if I had eaten out.
新しい服を買ったつもりで、そのお金を旅行に回した。
I acted as if I had bought new clothes and put that money toward a trip.
3With the plan to
What you meant to do, then what you did for it; the result often turns out different: 「ご馳走するつもりで行ったのに、おごってもらった」 (I went planning to treat them, but they treated me).
ご馳走するつもりで行ったのに、おごってもらうことになった。
Despite going with the intention of treating everyone, they treated me.
何も買わないつもりで新しく出来たショッピングモールへ行ったが、色々買ってしまった。
I went to the newly built shopping mall without any intention of buying anything, but I ended up purchasing various things.
4Thinking you had
「Vた/Nのつもりで」: you believe you have done something, but you haven't; often followed by のに: 「新鮮な魚を選んだつもりで買ったのに…」 (I bought it thinking I'd picked a fresh fish, but...).
新鮮な魚を選んだつもりで買ったのに、パックから出したらものすごいにおいがした。
I bought this fish thinking I'd picked a fresh one, but when I took it out of the pack it smelled terrible.
鍵をかけたつもりで出かけたのに、帰ったらドアが開いていた。
I went out thinking I had locked the door, but when I got back it was open.