to a fault

(do sth) to a fault (to do something so very well or to be something so good that it is almost bad) — слишком (уж), чрезмерно, через край; донельзя; патологически (честный, чистоплотный, порядочный, пр.)

Example 1: Jake is honest to a fault and will not say anything unless it is the absolute truth. (idiomconnection)

Other examples: expansive, generous to a fault / courteous to a fault/ pious to a fault /sensible to a fault / meticulous to a fault /respectful, obliging to a fault / greathearted to a fault / shy to a fault / slavish to a fault / devoted to a fault / sensitive to a fault / professional to a fault ...