"This afternoon I had put myself down on this sweet spot, very tired of painting [with a view of the old castle of Vorden] .. .. I was completely immersed in thinking of You.. .I would rather like to.. ..thank you, dear and beloved Lady, for the right judgments and remarks which You gave me in this [your?] sweet letter. I solemnly promise you that I will use them for my benefit, and will spent all my powers as an artist, to make your attentions more worthy to me. (translation from Dutch, Fons Heijnsbroek)."
January 1, 1970
https://en.wikiquote.org/wiki/Johannes_Warnardus_Bilders