Enthusiastic about is a workhorse phrase in applications, self-introductions and cover letters, which is exactly why it wears out. The replacements are plentiful, but two things break sentences: choosing the wrong intensity and pairing the word with the wrong preposition.
What enthusiastic promises about you
Enthusiastic about signals genuine positive energy toward something, stronger than interested but less extreme than obsessed.

It appears in applications because it promises motivation, and Merriam-Webster's thesaurus places it among the eager and keen family. On an intensity scale from indifferent to obsessed, it sits comfortably in the upper middle.
The intensity ladder
Keen is brisk and likeable, eager adds readiness to act, ardent adds visible passion, and zealous risks sounding excessive.
| Word |
Intensity |
Safe with |
| keen |
brisk |
roles, hobbies, opportunities |
| eager |
ready to act |
tasks, starts, learning |
| avid |
committed habit |
reader, cyclist, supporter |
| ardent |
visible passion |
advocate, supporter |
| zealous |
risk of excess |
needs supporting context |
Ladder positions shift with the noun: an avid reader is normal, a zealous reader is alarming.
Prepositions that change with the word
Keen and enthusiastic take on or about, eager takes to with a verb, and avid and ardent sit directly before nouns.
Wrong: ardent of the plan. Right: ardent supporter of the plan. Wrong: eager about joining. Right: eager to join. Wrong: keen to hiking. Right: keen on hiking. The wrong preposition is the most common error in this family, and spell-checkers sail past every one of these.
Formal writing without flat enthusiasm
In formal writing, prefer committed to, keen to contribute or looking forward to, which show enthusiasm through action verbs.
Repeating enthusiastic in one letter reads as effortful. A sentence like I am keen to contribute to the programme's outreach work keeps the energy while showing the action behind it, which is what formal readers actually want to see.
FAQ
What can I write instead of I am enthusiastic about this role?
I am keen to contribute to this role or I look forward to growing with the team keep the energy with more action.
Is keen British English?
It is common across varieties and reads naturally in Singapore workplace English.
Can zealous ever be positive?
Yes, but it needs supporting context because it often implies too much of a good thing.