Yes, a better word is probably earnestness. Early (generally pre-1970s) Krishnamurti sometimes used the word sincerity in a very particular way, that is, in relationship to belief and faith (as in ‘sincerely held beliefs’). This is not of course the way that the word is used conventionally, where sincere can mean “sound, genuine, pure, true, candid, truthful” (traceable to its latin meaning of “whole, clean, pure, uninjured, unmixed”). For this latter purpose Krishnamurti used the word earnestness. One gets a gist of Krishnamurti’s different usages for these words from the following two excerpts:
Surely, there is a difference between sincerity and earnestness. One can be faithful to an idea; to a hope, to a doctrine, to a particular system; but merely copying, pursuing an idea, or conforming oneself to a particular doctrine - all of which may be called sincerity - will surely not help us to clear up the confusion in ourselves, and so the confusion about us.
So, it seems to me that what is necessary is earnestness - not the earnestness that comes from merely following a particular tendency, a particular path but that earnestness which is essential in the understanding of ourselves. To understand ourselves, there need be no particular system, no particular idea. One is sincere only in regard to a thing, to a particular attitude, to a particular belief, but such sincerity cannot help us; because, we can be sincere and yet be confused, foolish and ignorant. Sincerity is a hindrance when it is mere copying, trying to follow a particular ideal; but earnestness is quite a different thing. To be earnest is essential not in the pursuit of anything, but in the understanding of the process of ourselves (Paris 5th Public Talk 1950)
We think that by following a formula - for peace, for meditation, for discipline, for reaching a particular ideal, and so on - we become very responsible, very earnest, very serious. I very much question such a mentality because I feel that such a person is not really earnest; he is merely copying, following, ridden by authority. A follower, surely, is never an earnest person and it is only to the earnest that life reveals itself, not to the follower of a formula. Life is for the earnest, and the earnest one is not he who merely seeks an escape from conflict and sorrow, from the various problems, accidents and incidents of life. The earnest man has not a ready-made solution with which he approaches life’s problems. The one who is really earnest is he who enquires…. I think earnestness is essential for any man and especially for one who is trying to find out what is true, what is the meaning of this existence (Madras 4th Public Talk 1958)
All I meant with regards to dialogue, is that it requires earnestness, honesty, vulnerability, genuineness, an open candid approach (rather than one of withholding, being evasive, having ironic distance, dissembling, etc).
I’m not sure which of the things I’ve written you are referring to here, but it is certainly true that Buddhism is an incredibly complex, often beautiful, often ungraspable(!) series of religious movements and philosophical developments, that I was fortunate enough to study during my MA (hence the perhaps rather scholarly niceties!). I still find the relationship between Krishnamurti’s teachings and Buddhism a source of fascination - but one mustn’t compare (too much!!) of course