not for lack/want of trying

not for (a) lack of trying

Despite putting forth a decent amount of effort or energy. A: "So, did he agree to go on a date with you?" B: "No. Not for lack of trying, mind you." I'm sorry your team lost, but it wasn't for a lack of trying!
See also: lack, not, of, trying

not for lack/want of ˈtrying

used to say that although somebody has not succeeded in something, they have tried very hard: He’s had no success in finding a job, though not for lack of trying.
See also: lack, not, of, trying, want