So Reimu set up Suika to get married by sealing her sake. Now the question I want to ask is who is the groom; Reimu herself or someone else?

I think it's: Suika can't have sake at her wedding.

The chain makes me think of that term the old ball and chain.

Dr_Z said:
The chain makes me think of that term the old ball and chain.

The shackles of marriage as it were.

Krugger said:
So Reimu set up Suika to get married by sealing her sake. Now the question I want to ask is who is the groom; Reimu herself or someone else?

Must be someone else.I think Suika is marrying is because Reimu forced her to do it,so as to send her away.As for the sealing of her gourd,it must be to prevent her from going drunk and misbehaved,and sent the groom packing in the end.