The correct spelling for the phrase "wast insincere with" is actually "thou wast insincere with" as it is in Old English or Shakespearean English. The "th" sound was later replaced with the "w" sound in Modern English. The correct phonetic transcription for the pronunciation of "wast" would be /wɑːst/ with a long A vowel sound and a voiced th sound. "Insincere" would be transcribed as /ɪnsɪn'sɪr/ with stress on the second syllable and a silent "e" at the end.
"Wast insincere with" is an informal and somewhat uncommon phrase that combines archaic language with modern slang. Breaking down the phrase, "wast" is an archaic second-person singular form of the verb "to be" in the past tense, and "insincere" means lacking genuineness or honesty. "With" is a preposition indicating association or accompaniment.
Therefore, "wast insincere with" suggests that someone was being dishonest, disingenuous, or deceitful in their interactions or communications. The use of "wast" gives it a poetic or old-fashioned tone, evoking a sense of antiquity or formality. This phrase typically implies a deliberate intention to mislead or deceive others.
The connotation of "wast insincere with" carries an element of betrayal or disappointment, as it suggests that the person being addressed has failed to be genuine or truthful in their interactions. It implies that the speaker expected honesty and openness from the individual but has now discovered that they were being insincere.
Overall, "wast insincere with" is a unique and uncommon phrase that denotes someone's past insincerity, using poetic language to convey a sense of dishonesty and disappointment.