Short answer. Yes. Rule 10, Section 3 directly requires the court to refuse leave to amend once past the amendment-as-a-matter-of-right stage if it appears the motion was made with intent to delay the case. If the court found that intent after notice and a hearing, denying the amendment is exactly what the rule contemplates.
What the law says
such leave shall be refused if it appears to the court that the motion was made with intent to delay
Rule 10, Section 3 — Amendments by leave of court. Read the full provision →
Substantial amendments need leave of court
Once a case has moved past the point where a pleading can be amended as a matter of right, Rule 10, Section 3 requires that substantial amendments may be made only upon leave of court. That means the amendment is no longer automatic; a party has to ask the court's permission, and the court has real discretion over whether to grant it. This is the stage the rule is describing when your motion to amend was evaluated and denied.
When the court must refuse leave
The same section does not leave that discretion open-ended. It tells the court when leave shall be refused: if it appears that the motion was made with intent to delay, if the amendment was aimed at manufacturing jurisdiction the court would not otherwise have, or if the original pleading stated no cause of action from the beginning that amendment could fix. A finding of delay is one of these named grounds, and it is squarely within what the rule directs the court to do, not a ground the court invented on its own.
The procedural protections that still apply
Even a denial grounded in intent to delay has to follow the process the rule sets out: the matter is decided upon motion filed in court, and after notice to the adverse party, and an opportunity to be heard. If the court ruled without giving you the chance to be heard on the motion, that procedural step, rather than the substantive finding of delay itself, would be the thing worth examining. But a finding of delay reached after proper notice and hearing is a recognized basis for the court to deny leave, not something outside its authority.
What a denial does not do to your existing case
A refusal of leave to amend is a ruling on that particular motion; it does not by itself dismiss your complaint or end the case. Your original pleading, as it stood before the proposed amendment, continues to govern the proceeding unless some other order changes that. If you believe the court's finding of delay was mistaken, or that the process leading to the denial fell short of the notice and hearing the rule requires, that is a distinct question from whether Rule 10, Section 3 permits refusal on delay grounds at all, since on that point the text is unambiguous.