Hmm sorry to "revive" this thread...
"Pure" and "blessing" may have different meanings, depending on the cultural context.
In traditional Buddhist countries, "pure" often means free from the so-called 3 (or 5 in Mahayana teachings) poisons: ignorance (meaning not understanding how things really are, and taking what appears as having intrinsic existence), attachment (meaning exaggerating the positive qualities of something and desiring that something), aversion (meaning exaggerating the negative qualities of something and rejecting that something), pride (meaning the belief that you're somehow more special or more important than others and thus belittling others) and envy or jealously (due to the belief in one's superior importance, having resentment about the happiness that others enjoy).
(See also
http://en.wikipedia.org/wiki/Kleshas_(Buddhism)#Five_poisons )
In the Vajrayana teachings it can also mean "free from the three spheres", a rather curious way of describing subject/action/object — the belief that each has separate, intrinsic existence. Buddhism encourages the training in viewing things as they are: interdependent, inter-related, co-existing and co-appearing — Interdependent Co-arising or Dependent Co-origination. So "purity" can mean, in this context, that we should learn to view things as they really are, interdependently co-arising, and not as separately existing by themselves.
"Blessing" also has a different contextual meaning. The literal translation from the Sanskrit, rendered in Tibetan, simpl means "wave of influence". A person is "blessed" by recognizing certain attributes or qualities of a good practitioner, teacher, a Buddha, whatever, and, feeling inspired by them, tries to emulate those same qualities. Due to interdependent co-arising, we recognize these qualities in others because we have the same potential as them, and this allows us to work with ourselves to fulfill that potential and give rise to those qualities in ourselves.
So one way to interpret the monk's answer is, "if you are able to think of your transition as being free from the 3 (or 5) poisons, or free from the three spheres, then you will be able to go through it and, as a result, achieve the same qualities, benefits, and accomplishments as others who did the same".
It's rather a mouthful, and a very profound answer.
My own attempt to make it simpler... what are the motivations behind your transition? If they're stained by the belief that somehow you will reach everlasting happiness through it, or somehow it will make you a better person (or superior to others), then surely you will not achieve any positive results with that. On the other hand, if you understand that everlasting happiness will not come from your transition, and that you won't be neither a better or a worse person because of that, but, instead, by emulating those who did train their minds and accomplished the goal of reaching everlasting happiness, then, whatever the results of your transition, you will achieve the same goal. Even more simply: everlasting happiness will not come from your transition, but from the mindset you have.
A bit tough, isn't it? Like my own teachers keep repeating, Buddhism is harsh, rough, and direct to the point, and the more it is practice, the more it makes us feel uncomfortable. Which is great: if we feel uncomfortable, we start questioning our own ego, and that's supposed to be the whole point of the training.