assuredly, beyond the shadow of a doubt, certainly, come what may, definitely, doubtlessly, for certain, indubitably, inevitably, inexorably, undoubtedly, unquestionably, without doubt, without fail
English Collins Dictionary - English synonyms & Thesaurus
1 adv You use surely to emphasize that you think something should be true, and you would be surprised if it was not true.
ADV with cl/group (emphasis)
You're an intelligent woman, surely you realize by now that I'm helping you..., If I can accept this situation, surely you can.
2 adv If something will surely happen or is surely the case, it will definitely happen or is definitely the case.
FORMAL ADV with cl, ADV before v
He knew that under the surgeon's knife he would surely die..., He is an artist, just as surely as Rembrandt or any other first-rate portrait painter is one.
3 If you say that something is happening slowly but surely, you mean that it is happening gradually but it is definitely happening.
slowly but surely phrase PHR with cl
Slowly but surely she started to fall in love with him...
Translation English Cobuild Collins Dictionary
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