Some common words that you can replace.

Instead of Happy you can use:

• Glad
• Jovial
• Thrilled
• Cheerful
• Merry
• Contented
• Pleased
• Delighted
• Jolly
• Elated

How to say you are not sure:

• I guess
• It seems
• It looks like
• It appears
• Apparently
• Probably
• Perhaps
• well

Something new😁: Bookkeeper is the only English word with three consecutive repeated word.b-oo-kk-ee-per.

Formal and Informal words:  https://youtu.be/i17E6KPahaY