States a firm intention or plan to do something. Stronger and more considered than a passing wish — 'I intend/plan to ~'.
[Verb dictionary form] + つもりだ / [Verb nai-form] + つもりだ
明日から走るつもりです。
Ashita kara hashiru tsumori desu.
I intend to start running from tomorrow.
走る (run, dictionary form) + つもりです (intend to)
負けるつもりはない!
Makeru tsumori wa nai!
I have no intention of losing!
負ける + つもりはない — negating つもり ('no intention of') is stronger than 負けないつもり
夏休みに国へ帰るつもりだ。
Natsuyasumi ni kuni e kaeru tsumori da.
I intend to go back to my home country during summer vacation.
帰る (return, dictionary form) + つもりだ (intend to)
• To say you intend NOT to do something you can use either the nai-form + つもり (行かないつもり) or つもりはない (行くつもりはない, 'no intention of going'). • つもり can also express a subjective self-image: 若いつもりだ ('I think of myself as young'). • 予定 (よてい) is used for fixed, scheduled plans; つもり is personal intention.
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones つもりだ is tested against.
予定 is a set, often externally-fixed schedule ('the meeting is scheduled for 3'); つもり is the speaker's personal intention, which can still change.
The volitional expresses on-the-spot will or a suggestion; つもり expresses a pre-formed, settled plan.
たい is a want/desire; つもり is a decided intention to act on it.
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