be more than willing but lacking in strength(/means); cannot do as much as one would like to;find it difficult to fulfil one’s promises;one’s ability falls short of one’s wishes (/desire); the spirit is willing but the flesh is weak; unable to do what one wants very much to
❍ 你有多大本领？上头说了一句大开门的散话，如今又要一句连转带煞，岂不～呢？(《红楼梦》1029) What great skill have you got? You’ve just made a fresh opening by bringing in something ir relevant. If now in one line you try to round it off and revert to the main theme,you’ll find you’ve bitten off more than you can chew.
❍ 我原也想好好照顾您的，可是这几年人老了，耳聋眼花的，～。(田汉《关汉卿》25)For a while I thought I’d be able to look after you.but these last few years my age is beginning to tell on me.Now even my eyes and ears fail me.I can’t do as much as I’d like to.
❍ 只是兄弟一个人也还是～！ (茅盾《子夜》82) I am all for the scheme myself; the only trouble is that I haven’t the resources.
❍ 赵姨娘叹气道： “阿弥陀佛！我手里但凡从容些，也时常来上供，只是 ‘～’。”(《红楼梦》292)❶“Amida Buddha!” She sighed again.“If I’d only more in hand I’d be giving oftener. I just haven’t the means.”
❷“Holy Name!”said Aunt Zhao. “I’d do it oftener if things were a bit easier; but you know the saying: my heart is willing but my purse is lean.”
心有余而力不足
mind is willing,but flesh is weak; one’s ability falls short of one’s wishes;unable to do what one wants very much to do;be more than willing but lack the power to do sth
心有余而力不足xīn yǒu yú ér lì bù zú
心里很想干，但力量不够。unable to do what one wants very much to do, one’s ability falling short of one’s wish, be willing but lacking the power to do