Finding the answer is the mystery of "Xin"

Get together for a new love (word 1) Xin (Xin+Huanyouqin = Xin)

Have the right to make a new love immediately (word1) xin (new+huan-right-li = xin).

One load is only ninety-nine (one word) hin (one load = 100 kg, which means 1 kg, and+kg = hin).

Although I am short of twelve taels, I am also happy (word one) (missing twelve taels = owed 1 kg = happy, happy = happy in my heart)

Insufficient weight (word 1) Xin (Jin)

Short Jin is short of two (one word) symplectic (short Jin)