If I were you I wouldn't use the word "bereavement" since it's such an overworked noun. It's almost exclusively reserved for formal prose. How many times have you heard people around you use that noun in daily conversation?
Write your email in a natural manner, as though you're talking to the other person, as if you're in the same room with that other person. Try to be sincere, considerate, and stay away from words like "bereavement" which belong to another bygone era.
"Should I include any personal anecdotes regarding the deceased in my email?"
By all means. Such true anecdotes make your message more meaningful by showing why you're genuinely sorry for the loss. It also helps the receiver ease the pain a bit by reminding all the good things that the deceased have done while alive.
This is a day to be respectful, mournful, but also positive to the extent possible. Personal anecdotes are an excellent way to show the silver lining around the dark cloud and remind us that, despite the loss, there is still something to gain from remembering the best about the one who is gone. Make it short, personal, and sweet.
For example:
"If Shirley had not supported my XYZ membership with that generous recommendation letter she has written back in 1996, I would've never be where I am today. That's for sure."
"How can I forget the day when Bob has taken our son Rajeev on a personal campus tour and thus played a crucial role in Rajeev's decision to enroll in Ohio State?"
"Remember the day when both of you showed up at the lake and we had that great boat trip to Rockville? That'll always remain one of our fondest memories."
"As you know, Bob and I served together in XYZ. I'll never forget the way he used to sing for the whole company at nights on that old guitar that eventually fell apart and we burned it at a bonfire."
"Which subject lines should I use in my email?"
For your condolence email or sympathy email you can use these subject line and body templates after replacing the place holders with your own personal event information, as appropriate.
CONDOLENCE EMAIL SUBJECT LINES:
Please accept my condolences. Writing to share your great loss... With deepest sorrow and sympathy... Shaken by your great loss... Heard the tragic news... Our thoughts and best wishes are with you...
Here are some condolences email samples...
EMAIL BODY:
Dear Pat,
We were stunned when we heard the bad news. Please accept our condolences for Bob’s passing away. His loss has grieved us all especially since we had no idea it was coming. We hope his fine memory will be of some comfort to you in these most difficult days. With our heartfelt sympathy and best wishes,
Your friends, Jack and JamieDear Pat,
The news of Caroline’s death was such a blow I was wrecked with grief when I heard it just hours ago. I can imagine the kind of shock you must be in. But allow me to say that at least she is not in pain anymore and the good Lord I’m sure is taking good care of her in His infinite compassion. I hope to visit you soon and share my sorrow in person. Until then please accept my condolences.
Yours in friendship, JamieDear Pat,
Losing a loved one is never easy; I know that from personal experience. But still, it’s impossible to get used to it in any definition of the term either. I am very much shaken by Bob’s death and wanted to send you these few lines to let you know that I’m here to share your great sorrow. Bob was such a sweet man full of kindness and love and he will be sorely missed by us all. May he rest in peace.
With my deepest sympathies, Jamie Dear Pat,
At this moment of great loss for you and your loved ones, I'd like to send you all our love. Bob's passing away was so unexpected and so untimely. He still had good years ahead of him. The only way we can cope with this tragedy is to remind ourselves that there is a Heaven and we're certain Bob is there, reaping the divine fruits of a life lived well. His fine memory will be with us as long as we live.
Please let us know how we can help you with anything.