Regarding "troth," it was used in traditional wedding vows. When I was planning my wedding in 1989, I was researching vows. I'd heard Pledge thee my troth before, but didn't really know what is meant. It boils down to promising to be faithful.
We used Church of Canada vows. We were married in the First Presbyterian Church in Old Cowtown, Wichita, by a Presbyterian minister. DH was Episcopalian, and I was Presbyterian. Our minister had to agree to use the Church of Canada vows.
"I take you to be my wife/husband; to laugh with you in joy; to grieve with you in sorrow; to grow with you in love; and to be faithful to you alone as long as we both shall live."