"could have sworn" meaning in English

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      "expansion": "could have sworn",
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  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
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      "examples": [
        {
          "text": "\"You lost your bracelet?\" \"Yeah, but I could have sworn it was in the kitchen on the table when I last saw it.\"",
          "type": "example"
        }
      ],
      "glosses": [
        "Is very sure about; especially when the thing in question is apparently not the case or could be doubted."
      ],
      "id": "en-could_have_sworn-en-verb-lcYMGUV0",
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      "raw_glosses": [
        "(informal) Is very sure about; especially when the thing in question is apparently not the case or could be doubted."
      ],
      "synonyms": [
        {
          "word": "could've sworn"
        }
      ],
      "tags": [
        "informal"
      ]
    }
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  "word": "could have sworn"
}

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      "expansion": "could have sworn",
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  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
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      "examples": [
        {
          "text": "\"You lost your bracelet?\" \"Yeah, but I could have sworn it was in the kitchen on the table when I last saw it.\"",
          "type": "example"
        }
      ],
      "glosses": [
        "Is very sure about; especially when the thing in question is apparently not the case or could be doubted."
      ],
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        [
          "sure",
          "sure#English"
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        "(informal) Is very sure about; especially when the thing in question is apparently not the case or could be doubted."
      ],
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        "informal"
      ]
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  "synonyms": [
    {
      "word": "could've sworn"
    }
  ],
  "word": "could have sworn"
}