• It is safe to say [ or It can be said with confidence ( or assurance )] that diesel oil is preponderantly used.
• We can state with assurance that ...
• It is safe to say [ or It can be said with confidence ( or assurance )] that diesel oil is preponderantly used.
• We can state with assurance that ...
Циммерман М., Веденеева К.. Русско-Английский научно-технический словарь переводчика. Russian-English scientific dictionary for translators. 2012