Your 50th anniversary toast needs to be a message of love and congratulations.
If it is your 50th anniversary then you need to thank the guests for coming and helping you celebrate. I am sure you will want to thank your partner for their love and support during the last 50 years. Maybe talk about when you realised that they were the one or when you first met or a funny uplifting story from your years of marriage. A nice way to end the toast will be to present your partner with a gift.
If you have been asked as a friend to make the toast then you can talk about when you first met them and how they are an inspiration to you. Raise your glass to toast the happy couple, there will be lots joining you.
If you want to extend your toast into a speech you could talk about fun times shared, their children and grandchildren, their hobbies and successes.
You could add important news events that from the year they got married, or the frontpage from the local newspaper always brings some laughs, just visit your local papers offices or the local library to see a copy.
1958 - Explorer Hillary arrives at the South Pole, Bridge on the River Kwai is the top grossing film, Elvis Presley is inducted into the army.
1959 - Ben Hur is the top film this year, Fidel Castro assumes power, Alaska and Hawaii become the 49th and 50th states of America.
Good luck with your toast, if you feel you want some support get other friends and family members to say something as well. Hope you get to enjoy the day!