certainly, doubtless
慥 centers on a state of firm certainty: something is definitely true, without doubt.
慥 combines 忄 (heart/mind) with 造, which likely contributes the sound ゾウ and may carry a sense of building or establishing, suggesting a firmly settled state of mind.
The heart radical 忄 beside 造 (to make/build) suggests a mind that has built a firm conviction: it is certain and without doubt.
For ゾウ, imagine a zō (象, elephant) standing firmly in your mind, its certainty as solid as its huge body: zō -> ゾウ, and your heart is convinced.