Dearest [name of Sister-In-law],
Congratulations on your 25th Wedding Anniversary!
We are so happy to have you in our family. The day my brother married and brought you into our lives and family, you really made a big place in our heart by being you and so delightfully showing us the best man he was in your presence.
This wedding anniversary definitely calls for huge celebrations. Since Day 1, Bro and you have shared an incredible knot that goes beyond blood-ties and friendship. You are the cutest couple living so far in the world, live happily and enjoy your most beautiful day. I can say you both are a legit couple for me and wish you more happiness coming on your way.
I hope with each passing year, this strong attraction, respect and love never waives and in troubled times you always remember your humble beginning with nothing but love. I wish you a lifetime of happiness, peace and contentment, may you & bro live long and look after each other like you always do and always have.
May you have such a beautiful life ahead. Once again, Best Wishes on your special wedding anniversary.