Manners (Mind and Spirit)
The Significator of Manners is Mercury placed on the Ascendant (twelfth House side but only just over 3 degrees away and in the same sign of Libra). Not only conjunct the Ascendant, Mercury has mutual reception through rulership with Venus (in Virgo), which involves Venus in the assessment of the mind. As a benefic Venus will strengthen the mind. Mercury also sextiles Saturn which is a malefic, and not well placed by Sign. Not a particularly strong relationship but I'd say it added something of a streak of either reticence or something of a lack of self belief or self doubt. It can also give some interest in 'science' (in it's original meaning of structured knowledge), desire to solve mysteries, or further understanding.
The balance between reason and instinct within the mind is shown by Mercury and the Moon. Stronger Mercury gives a more rational approach, stronger Moon gives a more instinctual, approach. Here Mercury and the Moon are both strong - However the Moon is in its own rulership, Mercury gets its dignity through mutual reception, so I'd say that the instinct or feelings side of the mind is a little more dominant. This works well with the temperament which is more phlegmatic than sanguine.
Mercury is fast and in an air sign, Lilly says this shows a strong memory.
The Moon squares Mercury , so that should indicate some tension between instinct and reason - perhaps showing up as either something of a distrust of reason as a way of seeing the external world or alternatively as suspicion of feelings or instinctive reactions and a desire to impose reason, which never quite works.
So we have a good mind good powers of memory and good and likely more dominant instinctual or non rational faculties.