Jane Austen very cleverly uses Elizabeth as first-person observer, to comment about her parents' ineffectual and unsatisfying (at least to her father) bond. The fact that Elizabeth is the one who shares her observations, gives greater credence to what is stated in the text. Elizabeth is the most intelligent, insightful, philosophical and wisest of all the females in the Bennet household. Her opinion is therefore of greater value than that of any of the other women. She is more like her father than any of her siblings and her mother is his complete opposite. We can therefore respect her thoughts and do not question her integrity in this regard.
The first line implies that Elizabeth's opinion of conjugal bliss, if it had been derived from observations of her family alone, would not have been pleasant, implying that she indeed saw a lack: 'she could not have formed a very pleasing opinion of conjugal felicity or domestic comfort'.
Furthermore, Austen masterfully uses euphemism to describe Elizabeth's observations. The style and tone is not harsh, overly critical or damning, but herein lies the irony. By employing these soft descriptors, the failure of the Bennet's marriage is greatly emphasised. It is often a convention by those who criticise to use euphemistic language to add a greater sharpness and inciseveness to their criticism, the depth of which is only realised and understood or appreciated later, in an afterthought (when the opportunity to respond has been lost!) Instead of calling Mrs Bennet an idiot, she has 'weak understanding' and instead of saying that she is narrow minded, she has an 'illiberal mind'. The text is rich with such imagery.
Austen, throughout this section of the text, makes generous use of alliteration and assonance for emphasis: the 'f' - sound is constantly repeated - 'from', 'family', 'formed', 'felicity' etc. The repetition of the 'ou' and 'eau' sounds: 'youth', 'humour' and 'beauty' is also noticeable.
The rich use of adjectives also enhances the idea of Elizabeth's displeasure at how her father treats her mother and does not show her much respect, so much so that 'he exposed his wife to the contempt of his children'. Elizabeth finds this reprehensible but has learnt to forget it - 'she endeavoured to forget what she could not overlook'.