Here the Father refers to his Son as “my Well Beloved”. Originally Oliver Cowdery wrote simply “my beloved” in 𝓟; later he supralinearly inserted the word well (with heavier ink flow). This correction, probably made when Oliver proofed 𝓟 against 𝓞, undoubtedly restored the reading of 𝓞 (no longer extant here) since “my Beloved” is perfectly acceptable.
Normally, the Book of Mormon uses beloved without any preceding well, with the following examples and accompanying statistics for the original text:
“my beloved brethren” 59 times
“my beloved son” 8 times
“my beloved brother” 6 times
“my beloved” 4 times
“my beloved people” 1 time
“my best beloved brethren” 1 time
“my dearly beloved brother” 1 time
The only other occurrences of the phrase “well beloved” (two of them) are found in an Isaiah quotation from the King James Bible, in 2 Nephi 15:1. Of particular interest here is that Oliver Cowdery initially omitted the well from the first instance of “well beloved” in that passage (for discussion, see under 2 Nephi 15:1).
Summary: Maintain Oliver Cowdery’s inserted well in Helaman 5:47 (“because of your faith in my Well Beloved”), a correction undoubtedly based on the reading in 𝓞, no longer extant here.