In an everyday email or Slack message, write "I'll try" or "I'll do my best" — not "endeavour." To a US, UK, Canadian, or Australian ear, "endeavour" in a normal message sounds like a line from a terms-of-service page, not something a colleague would say. "I'll try" reads as more competent and more human, and it commits you just as clearly.
A lot of capable speakers learned "endeavour" as the polished, professional word for "try," so they reach for it to sound serious. The opposite happens: the high-formality verb reads as corporate boilerplate and distance. Native speakers keep it on the shelf for everyday messages and downshift to "try" or "do my best."
Save "endeavour" for formal legal or corporate commitments — and even there, "we'll endeavour to..." can sound like you're hedging on a promise rather than making one. (Note: "endeavour" in UK spelling and "endeavor" in US spelling are the same word. The issue here is register, not spelling.)
Name what you'll actually do instead of reaching for the formal verb:
Instead of
"I will endeavour to get back to you by Friday."
Write
"I'll try to get back to you by Friday."
"Endeavour" sounds like a customer-service script; "I'll try" is what a colleague actually says — direct and warm.
Instead of
"We will endeavour to resolve your issue as soon as possible."
Write
"We'll do our best to sort this out as soon as we can."
Stacked formality reads as boilerplate that's dodging a commitment; the plain version sounds like a real person who will act.
Instead of
"I'll endeavour to make the standup."
Write
"I'll try to make the standup."
For a routine internal message, "endeavour" is overdressed; native speakers downshift to "try to make it."
Practice clearer workplace phrasing on real messages.
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