这个词语有一点儿奇怪。 是诗意的话语， 不是白话。 “Reservedly it be” = ‘’reservedly it is’’ = “it is reservedly…” = “it is with humility” Reserved 的意思是：特色是克己，是沉默的，谦逊的 按照我的看法，这里的意思是谦逊的。

The whole sentence isn't really well-written, but "reservedly it be" is the subjunctive form. Perhaps the idea was to mean something like "although my apology seems reserved", but I would have rephrased that part slightly if I were to use the subjunctive.