We have no meanings for "know plainly" in our records yet.
1 As you speak in that way, I must let you know plainly what I feel.
2 I want to know plainly whether or not you are coming to my meeting to-morrow.
3 It is yours now, as you let us know plainly enough, but whose will it be if you should die?
4 If not, let me know plainly and at once; for afterwards there will be no time for writing, or for speech.
5 If you have reasons for not entering into my request, or for declining to concern yourself with it personally, let me know plainly and definitely.
6 "Such being the case," answered De Valence, "let me know plainly on what matter it is that you require my opinion?
Grammar, pronunciation and more
This collocation consists of: